A little trick for attaching a messenger line to wire is to unlay a strand or two for a few inches and then lay a small diameter messenger line against the wire. Then relay the strands around the messenger, thus trapping it. Use a little tape to keep the wire from unlaying as you pull it through all the twists and turns.
I have replaced many halyards, steering cables and centerboard cables over the years with this method.
Trying to tape a messenger to a greasy piece of wire is just asking for trouble.