IProperty dp = target.getProperty(sp.getName());
// create unknown property for the first time
if(dp == null && !target.hasResource(sp.getName())){
dp = target.createProperty(sp.getName(),IProperty.ANNOTATION_DATATYPE);
dp.setRange(new String [0]);
}
// copy string values if not there
dst.setPropertyValues(dp,src.getPropertyValues(sp));