I didn't want to reply, simply because I do not have experience with breeding retics specifically and felt there are plenty of other people on the board who could give a better answer, but since you haven't gotten any response yet...
I would try putting the female' shed in the male's enclosure rather than the male's in the female's, especially given that you seem to see the male being uninterested. I would palp your female, maybe she just isn't in season yet. If you aren't doing any seasonal changes to heating, they are probably going to establish a pretty random clock instead of matching their natural season. I feel like her being cool seeking is probably a good indicator she is building, but no good way to know without palp or ultrasound. When was her last shed?
Best of luck to you! Hopefully some more retic people with more experience under their belt respond, as of now I just keep retics and breed other (much easier) stuff.