How to remove fan clutch from water pump

I have a chevy 1500 pickup, v8 350. I am trying to replace the water pump but I cannot get the fan removed from the old water pump. The fan has a clutch on it and the shaft spins when trying to unscrew the fan from the pump shaft. Does anyone have any tricks for trying to get the fan loose?

http://www.toolsource.com/clutch-wrench-holding-tools-master-p-61432.html?osCsid=o4c3chq37ino24uubbehr9t6n2

Here’s what these fan clutch wrenches look like. You need one of these of the proper size to remove the fan clutch.

Tester