Don't know if it supports your (Axim?) x50v, but I am a satisfied user of PDAWIN.com's TV Remote Controller 5 on an iPAQ 3900. Check out their web site and see if it supports your PDA. It only cost US$15, and is well worth it, despite the lack of product support. I tried out a least a half dozen PDA remote control emulators before picking it. Two of my main reasons for choosing it were:
1. It uses full CCF files (not just the codes) and provides a pretty close approximation of a real Pronto (at least on the screen).
2. It supports an IR extender. Even though the iPAQ 3900 has a CIR interface, I found the range to be marginal without an extender.
YMMV.