you need to take the whole board out. in the back are the 2 push pin screws. squeeze the ends together and carefully push them through.
i left the little square of foam around and just removed the stock TIM. its a little stubborn but i used some acetone and then isprophyl and it came off ok.
spread a bit of as5, line up the pins and push 'em back through. remember to plug back in the fan and you're good to go.
its really pretty painless,i'v done it twice. be sure to gently push on each end ofthe fan and rock it a bit and then make sure its nice and flat to the core.
also, i find the rpms of that fan don't mea much. i can get the same temps at ~2000 rpm as i can with max.i use the ite smart guardien thats on your driver cd to control it.