What are you trying to do, remove the tank or replace the sender? The sender and fuel pump are accessible from under the vehicle (theoretically) without removing the tank. If you want to drop the tank, siphone out as much gas as possible, then find the two 'J' bolts at the forward ends of the two straps. Prop the tank in place with a floor jack (put a length of 2x6 or 2x8 on top of the jack so you don't punch through the tank. Remove the shiled under the fill neck and unclamp the hoses. Then remove the nuts from the 'J' bolts, remove the straps, and drop the tank. The hoses have to be coaxed through the opening in the frame, and it's a lot easier to deal with if the tank is empty.
The fuel pump is held into the tank by a lock ring, as you've probably already discovered.