I've been wanting to do this with my GC83 EDGE card. I'd appreciate if you keep this thread updated.
One question about the surgery on the PCMCIA card -- aren't those tabs meant to keep incompatible hardware from coming together??
EDIT: I was looking this up...
http://www.pcmcia.org/pccard.htmIs the PCMCIA port on the 1200/600 3.3v-capable? In this case, SonyEricssons specifications for the GC75 say "3 and 5 volt PC Card slots" so it might be a moot point.
Alas, my GC83 carries no such guarantee. :-(