I know this says "Resolved" but I'd like to interject.
All I found that I needed to create in put a new vehicle in the game was an ODF file for programming what it would do and a VDF file for what it would look like. I never had to mess with any DES, GEO or any other files. All of them work fine (with the exception of modding mission recyclers, which it always came up as an unhandled exception).
So far I've replaced the default vehicle with my own personal creation, (god modding, by the way. Will never release publicly :3 ) complete with air-to ground torpedoes

, a special breed of wingman called the Beetle, a down to earth, Fury-equipped vehicle, the smallest and fastest in the game, as well and god-modding every unit in the NSDF. It's enteraining to see a NSDF Recycler move faster than a stock Scout. XD I've also created a Kamekazi unit by modding the "gnavdrop" weapon to drop the nuclear device from one if the IA missions (the new file adequately called "gsuicide" :3 ), which instantly detonates and destroys everything within radar range.
One thing I've found... custom names will not appear on the HUD. They will appear as strange black and transparent boxes. If you know how to display names like that, please let me know, but I'm content with what I have.
I never had to mess around with any .map or .geo files, save for when I created the two custom vehicles themselves. I find it rather easy to mod the hell out of this game. My advice: Make sure everything is properly named and coded. Copy-Paste works wonders.

Additionally, a .inf file is not required to use a vehicle or weapon. If you identify a vehicle with no .inf file, it simply says, "avx.inf", assuming we are still talking about the American vehicle "x"
I haven't tried to use the vehicles in a DM or Strat, for good reason. I simply went into the campaign or into an IA mission with the proper Factory, modding to build the custom vehicle. As long as there is a proper .VDF and .ODF file, it works fine.
I wouldn't encourage custom vehicles in DM or strat, either. You can do anything to a custom vehicle, including adding a weapon like gsuicide, and you could always say it was something else...
DISCLAIMER: I have not tried and will not try to use this mod with multiplayer. I'm incredibly scared of playing the CCA campaign now because of what I've done. XD Rest assured, I stick to the stock vehicles, especially the Lunar Lander.