There are two approaches to this that I can think of. While I have never done this exact surgery, I have done lots of similar stuff. First ID the revision of motherboard you have. According to the photos at Amiga-Hardware there are at least two different RF units used (large one and a small one).
I would either use a Dremel to cut carefully cut away enough of the shield so I could see what I was doing, or just de-solder every through hole connection within the foot print of it and hope. Just be careful and it should be pretty easy. Try flux with solder braid and make sure to use enough heat to be quick about it.
