roger
cut a hole and save yourself a lot of trouble.
it is not that hard and is suggested in the owners manual.
this is a thread on how i fixed my '92 leaky grey water valve
http://www.airforums.com/forum...ead.php?t=4753 the only thing you need to be careful of is not to cut the tank sensor wires when you go at the tank box with the tin snips. there are a lot of them in there.
start slow. once you get going pry down the tin so you can see what you are cutting.
john