It ssounds as if the guy has thought htis out quite well.

You might want to look into business or professional licenses and look in to what address he uses for those. If he has different addresses on either states license, I would obtain copies, or at least copy the info to discredit the ex in court.

I guess the bigger question, to me anyway, is even if you have the order domesticated, if the guy has no official income, what are you going to gain?