I have in my notes that I made sometime ago some information that I was able to get from doing some searches on the Internet regarding this vehicle. The only thing that I was able to come up with which was helpful to me was that between March and April of 1945, the 17th Panzer Division's Pz Gren Reg 40 and the 17th Div. Begel Komp were issued them.
I was wondering if these were the special flak version of the Steyer that were made which had an open cab such as this one: http://www.leadwarrior.com/Lw35029-h.htm
or would it have been any of the Steyer 2000 transport versions that were produced with the gun mounted at the factory. I have read that a lot times, the towed gun were mounted on the cargo beds of vehicles in the field by the units to give them more Self-propelled vehicles. In addition, would the gun have been the standard Flak 38 or the 38/103 "Jabo Schreck" such as this vehicle: http://www.leadwarrior.com/Lw35030.htm
I am still doing some searches on the Internet when I can but have not come up with anything further.
Thank you in advance.