diff --git a/src/SerializedObject.cpp b/src/SerializedObject.cpp
index 8615bb0df3..fb30248f64 100644
--- a/src/SerializedObject.cpp
+++ b/src/SerializedObject.cpp
@@ -374,11 +374,15 @@ const SerializedType* STObject::peekAtPField(SField::ref field) const
 	return peekAtPIndex(index);
 }
 
-SerializedType* STObject::getPField(SField::ref field)
+SerializedType* STObject::getPField(SField::ref field, bool createOkay)
 {
 	int index = getFieldIndex(field);
 	if (index == -1)
+	{
+		if (createOkay && isFree())
+			return getPIndex(giveObject(makeDefaultObject(field)));
 		return NULL;
+	}
 	return getPIndex(index);
 }
 
@@ -392,7 +396,7 @@ bool STObject::isFieldPresent(SField::ref field) const
 
 bool STObject::setFlag(uint32 f)
 {
-	STUInt32* t = dynamic_cast<STUInt32*>(getPField(sfFlags));
+	STUInt32* t = dynamic_cast<STUInt32*>(getPField(sfFlags, true));
 	if (!t)
 		return false;
 	t->setValue(t->getValue() | f);
@@ -420,7 +424,11 @@ SerializedType* STObject::makeFieldPresent(SField::ref field)
 {
 	int index = getFieldIndex(field);
 	if (index == -1)
-		throw std::runtime_error("Field not found");
+	{
+		if (!isFree())
+			throw std::runtime_error("Field not found");
+		return getPIndex(giveObject(makeNonPresentObject(field)));
+	}
 
 	SerializedType* f = getPIndex(index);
 	if (f->getSType() != STI_NOTPRESENT)
@@ -626,7 +634,7 @@ STVector256 STObject::getFieldV256(SField::ref field) const
 
 void STObject::setFieldU8(SField::ref field, unsigned char v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STUInt8* cf = dynamic_cast<STUInt8*>(rf);
@@ -636,7 +644,7 @@ void STObject::setFieldU8(SField::ref field, unsigned char v)
 
 void STObject::setFieldU16(SField::ref field, uint16 v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STUInt16* cf = dynamic_cast<STUInt16*>(rf);
@@ -646,7 +654,7 @@ void STObject::setFieldU16(SField::ref field, uint16 v)
 
 void STObject::setFieldU32(SField::ref field, uint32 v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STUInt32* cf = dynamic_cast<STUInt32*>(rf);
@@ -656,7 +664,7 @@ void STObject::setFieldU32(SField::ref field, uint32 v)
 
 void STObject::setFieldU64(SField::ref field, uint64 v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STUInt64* cf = dynamic_cast<STUInt64*>(rf);
@@ -666,7 +674,7 @@ void STObject::setFieldU64(SField::ref field, uint64 v)
 
 void STObject::setFieldH128(SField::ref field, const uint128& v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STHash128* cf = dynamic_cast<STHash128*>(rf);
@@ -676,7 +684,7 @@ void STObject::setFieldH128(SField::ref field, const uint128& v)
 
 void STObject::setFieldH160(SField::ref field, const uint160& v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STHash160* cf = dynamic_cast<STHash160*>(rf);
@@ -686,7 +694,7 @@ void STObject::setFieldH160(SField::ref field, const uint160& v)
 
 void STObject::setFieldH256(SField::ref field, const uint256& v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STHash256* cf = dynamic_cast<STHash256*>(rf);
@@ -696,7 +704,7 @@ void STObject::setFieldH256(SField::ref field, const uint256& v)
 
 void STObject::setFieldV256(SField::ref field, const STVector256& v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STVector256* cf = dynamic_cast<STVector256*>(rf);
@@ -706,7 +714,7 @@ void STObject::setFieldV256(SField::ref field, const STVector256& v)
 
 void STObject::setFieldAccount(SField::ref field, const uint160& v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STAccount* cf = dynamic_cast<STAccount*>(rf);
@@ -716,7 +724,7 @@ void STObject::setFieldAccount(SField::ref field, const uint160& v)
 
 void STObject::setFieldVL(SField::ref field, const std::vector<unsigned char>& v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STVariableLength* cf = dynamic_cast<STVariableLength*>(rf);
@@ -726,7 +734,7 @@ void STObject::setFieldVL(SField::ref field, const std::vector<unsigned char>& v
 
 void STObject::setFieldAmount(SField::ref field, const STAmount &v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STAmount* cf = dynamic_cast<STAmount*>(rf);
@@ -736,7 +744,7 @@ void STObject::setFieldAmount(SField::ref field, const STAmount &v)
 
 void STObject::setFieldPathSet(SField::ref field, const STPathSet &v)
 {
-	SerializedType* rf = getPField(field);
+	SerializedType* rf = getPField(field, true);
 	if (!rf) throw std::runtime_error("Field not found");
 	if (rf->getSType() == STI_NOTPRESENT) rf = makeFieldPresent(field);
 	STPathSet* cf = dynamic_cast<STPathSet*>(rf);
diff --git a/src/SerializedObject.h b/src/SerializedObject.h
index 2e28fc958b..7ecd539eb3 100644
--- a/src/SerializedObject.h
+++ b/src/SerializedObject.h
@@ -51,6 +51,7 @@ public:
 	bool setType(const std::vector<SOElement::ptr>& type);
 	bool isValidForType();
 	bool isFieldAllowed(SField::ref);
+	bool isFree() const { return mType.empty(); }
 
 	void set(const std::vector<SOElement::ptr>&);
 	bool set(SerializerIterator& u, int depth = 0);
@@ -95,7 +96,7 @@ public:
 	const SerializedType& peekAtField(SField::ref field) const;
 	SerializedType& getField(SField::ref field);
 	const SerializedType* peekAtPField(SField::ref field) const;
-	SerializedType* getPField(SField::ref field);
+	SerializedType* getPField(SField::ref field, bool createOkay = false);
 
 	// these throw if the field type doesn't match, or return default values if the
 	// field is optional but not present