Hobbymodellbau Schmidt is an aftermarket model accessory manufacturer in West Germany.
From what I have been able to learn from the instruction sheet I have the company has manufactured two vacuform aftermarket kits for HMMWV's.
1. M996 Mini-Ambulance/M997 Maxi-Ambulance
2. C3I Shelter/MSE Vehicle
I may be interpreting the title block of the direction sheet wrong and it may be intended you build both types from the same kit. If anyone knows for sure, please let me know.
This conversion kit seems to be pretty rare. The items I have here did not come in the factory packaging so I don't have images of what they may look like. There is one sheet of vacuform and on instruction sheet that is 11" x 16".
Here is the instruction sheet:
Below are shots of the sheet of vacuform parts.