How does one remove the pins on the southbridge so that I can remove the heatsink assembly? (I hope the heatsink comes off easily)

What's the best way to remove/lift the silver finned aluminum part of the northbridge heatsink? (by the I/O panel of the motherboard) It's attatched there somehow.

I have no problem over the northbridge chip itself. The heatsink lifts right off there and I can see a loose square thermal pad in there. (brand new just taken out of the box motherboard)

Please spell it out clearly for me so I can do this. I'd like to replace the thermal material with Ceramique.