Sorry for the delay in getting back to you. I *used* to be very current on Palm development, but haven't done any of that in a while as we started using the web instead of resident Palm applications (we would just hit the web with our Palms or cell phones).
I do, however, know that you don't want to use FileMaker mobile for anything complicated. Something like HanDbase will be a better platform as it is a real database on the Palm yet offers the ability to talk to FileMaker Pro either through built in conduits or through SQL (which is much more interesting).
http://www.ddhsoftware.com/