What kind of paperwork do you have... and are you referring to Louisiana, or Los Angeles?
I recently went through the process of titling and registering a HMMWV here in California that only had one piece of paper: a notarized bill of sale from Alabama. I tried Mainley Title first... they assured me they could title it, then jerked me around for 6 months before they finally stopped returning any of my calls.
After Mainley Title, I contacted about a half dozen other title companies and was either told they couldn't title a Humvee, or was given another "assurance" that they could do it without any actual details being provided that I could verify. Overall, I got the feeling that those title companies were a ripoff... whatever method they had used to title Humvees before had ended... the loophole had been closed, so to speak.
Finally, after about 8 months of trying to rely on title companies, I got off my butt and drove up into the foothills to one of the smaller, more rural DMV offices. I spoke to a woman at the counter who was very helpful, and was told that all I had to do was take the vehicle to the local California Highway Patrol office and have their VIN Inspector check the vehicle and assign a VIN that the DMV computer could use as a "point of origin" to title and register the vehicle. The issue ultimately wasn't that it was a military surplus vehicle... it was that the vehicle didn't have a standard 17 digit VIN that the DMV's computerized system could recognize.
A few weeks later, I took the Humvee up to the CHP station to get inspected. The officer never asked for an SF-97 and was perfectly happy with the notarized bill of sale. After checking the truck to make sure there were no conflicting serial numbers... finding none, he riveted a metal CA Assigned VIN label to the body and signed off on the DMV form.
From there, I drove to the DMV office and gave them the signed new vehicle title application. About $2k in state fees and taxes later, I walked out with registration and license plates... the title arrived a week or so later.
So, I guess the short version is to avoid the title companies because they dont seem to know what they're doing anymore re: military vehicles. Find a small DMV office near you and go ask them in person. I would have thought that California, with all it's BS regulations, would have made it impossible to get a Humvee titled... but it was actually remarkably easy.
Find out from the source how easy or difficult your state is gonna make titling a Humvee... then go from there.