Hi,
I read your reply to RGrimm. "I just put the tongue jack down if I'm running on battery power alone. If I need to hook up the generator, I have to unhitch, as the tongue jack prevents the tailgate from going down all the way"
I had the same issue with my previous set up. My previous TT had an electric jack that didn't allow me to lower the tailgate when hitched. What I did was unbolted the jack from the frame, rotated it to where the tailgate can lower and bolted it in that position. Jack worked the same, just looked goofy.
Not sure if this can help you, just a thought.