FFB is a biotch to work with at times. You can do this, it's annoying but it works (in IE8 at least):
And that's pretty much it. Remember to delete all cookies and stuff when changing profiles.
- Open Internet Explorer .
- Go to Tools -> Internet Options
- Connections Tab
- Click on the "Lan Settings" button on the bottom
- Check the box that says "Use proxy server"
- Enter proxy settings
- click ok
- Keep IE open when using FBB