Andrea,
We're going to have to take this in a few steps, to make sure we get it right.. but lets start and see how far we get.
First, I read what you're looking for again, and it's a little different then I originally anticipated. Since the user is staying within Facebook, I think you mainly want to enable "Authenticated Referrals". This is the system where any links on Facebook to your Application will force the popup. This is Facebook's system, so it's easy to setup:
* Go to your Facebook Application configuration area in
developers.facebook.com/apps
* Go to Settings -> Advanced
* Set "Enhanced Auth Dialog:" to Enabled, if it isn't already
* Go to Settings -> Auth Dialog
* At the bottom, enable "Authenticated Referrals"
* For now, leave the other settings below at their defaults.
Now, please test the flow. When you click the App link from your page, the permissions popup should appear (if you haven't already granted permissions to the app). JFBConnect will -not- currently create the user from that popup, but we can set that up to happen easily once we're sure that the above is working right and how you'd expect.
Please test, and let us know!
Thanks,
Alex