Have they changed the instructions? I never noticed it saying anuyhing about removing the fan in the past.
Fitting can sometimes be a nightmare, if like me, you get the plastic pins bending on you. I might try again using the no fan method though, should be easier.
Its exactlly the same method as the intel stock cooler to mount. And unmounting is easy enough, just get a screw driver and turn the pin holder, and pull up.