Correct. however binarize will re-ID the objects on your wrp, so you will have to update the object ID's in you mission after each time you pass the wrp through binarize. You may want to note down the position from the object inspector tool to help you find the object easier...
how about
_mapfactobject = nearest [x,y,z, "type"]
_objectID = format ["%1", _mapfactobject]
?
Hope this helps.