Simon,
Your request is becoming quite popular. JFBConnect v4.2 does mostly support Authenticated Referrals (what you're looking to do), but it's not an automatic thing. We're planning to make it a full-fledged feature in v4.3.
However, until then, we have put together a guide on how to setup Authenticated Referrals:
www.sourcecoast.com/jfbconnect/docs/face...henticated-referrals
We've done a bit of testing, and things seem to work well, but your feedback would be most appreciated.
Hope that helps,
Alex