a interesting question. I have become with my Asus P750 PDA new destinator Software and maps. This destinator Software for PDA Version 7 can display speed limits, so i think the dESTINATOR Software engine can do that too. I copied the Maps of Destinator 7 to CF and it works. But there is no speed limit warnings.
only what not work: the Audio speaking. (it works with maps 7, but the speaking voice is very low. (gentle)