Why not invite each other to play a 1 pointer, or any other length?
FIBS will not prevent this, although it will warn you that the unlimited match will be lost if you accept.
Your client program, (presumably javafibs), may do something slightly odd, I'm not sure. I don't use it that much, for some reason. I think it's great. I just have a bad habit of sitting down and running telnet.
If all else fails, use the command line, which may be accessed through your clients' "terminal" or "console" window, or similar:
invite otherguy 1