ORRRRRR... you could just do what the previous owner of my XR7 did. When I bought the car, it was with the understanding that it needed a water pump. I told the guy I would buy the pump if he would change it before I picked up the car.
He could not figure out how to get it apart either (like many others, I am sure you have noticed) soooooo he took a torch and cut the bracket down the middle. Swapped out the water pump, then when he put it all back together, he got everything in place and lined up, then welded it back together.
He did a good enough job. After all he IS a weldor, and a pretty damn good one at that. I worked with him for about 5 years in a welding shop. ANYWAYS... it CAN be done that way, but the finished product will look a bit "backwoods" no matter how good you can weld.