Utah WMA rules?

[muzzle]

I just wanted to see if any one out there can help me out here. I have permission from a land owner to hunt a piece of private poperty that just so happens to be smack dap in the middle a a WMA. They have been giving rights to hunt the ground for many years now so this is nothing new and the F&G is aware of the arangement. The owner has an easement through the WMA and so I also can use that easement to drive through the WMA to get to the property. Now..in the rule book it states no motorized vehicles are allowed on the WMA..except with F&G permission, but I obviously have permission. Anyway, I was headed off the ground the other day and I pulled over to quickly look down a canyon to see if there was any water in a stock pond. It took me about 5 minutes to do so but in that time a D-bag on a horse must have seen me get out of my truck and called the F&G. As I came back up to the property for the night hunt, he was waiting for me at the private property boundery. He asked me if I had a map and all the other usual info. Long story short he says he is writing me a tresspassing citation because I got out of my truck. My problem here is that I can not find anywhere that says I couldn't get out of my truck. If I was on foot, I would have been perfectly legal as it is PUBLIC ground and I had as much right to be there as anyone did..so why tresspassing?? In the rules, it just says you can't drive on a WMA but I was obviously legal to be doing so and he admitted that. He said I had to drive directly to the property then I could go where ever I wanted to. Does anyone know of a rule that would prove I did anything wrong by stopping and getting out? If the rules do not cover this situation did he just pull that explanation out of his a$$? Should I fight this one?