XMPProperty existing = target.getProperty(sourceProp.getName());
if (existing == null) {
//simply copy over
target.setProperty(sourceProp);
} else {
existing.convertSimpleValueToArray(XMPArrayType.SEQ);
XMPArray array = existing.getArrayValue();
XMPArray otherArray = sourceProp.getArrayValue();
if (otherArray == null) {
if (sourceProp.getXMLLang() != null) {
array.add(sourceProp.getValue().toString(), sourceProp.getXMLLang());