I have that same model and don't even have the belly pan over the black tank. Fabricating a new one shouldn't take too much design work. It covers the tank which sits low and then has a bend to allow it to mate up with the rest of the underbelly which is a bit higher. Here are a couple of photos that I have on mine, dont know if they will help all that much.
The one shot I have with the cover, not pretty or refined.
Without the pan, but you can see how it needs to bend going toward the front: