Since
Sf is NOT a game that opens by an .exe (meaning.. you can't just open it from the desktop..) you can probably do this:
If you have Mozilla Firefox:
1. Press tools
2. Press options
3. Go to the "Advanced' tab
4. Press the " Network" tab
5. Press settings
6. Tick Manual Proxy Configuration
7. Now go find a proxy list and just put in the information :)
I don't have an i.p. ban so i can't test this. But it's just an idea.
(I also forgot to mention..
Sf and any other ijji game uses a website to launch their games.. so they probably get their i.p. from the web browser. Now somebody go test it xP)