Oilyfingers,
I meant to add above: Though I can't answer your question precisely, I have had no problems running LV Mobile produced WinMob 2003 code on the WinMob 5 or 6 devices, or WinMob5 code on the WinMob6 device. Of course, you do not then have access to the features specific to the newer WinMob OS (assuming LV Mobile supports them anyway).
Hope this helps a little,
Al