Facebook select friends and post UIDs to custom URL

I'm building a facebook connect application, and here's the specific use case I'm trying to solve (using the Facebook Connect Javascript toolkit - http://github.com/facebook/connect-js)

1. There is a link on a page that a user clicks to "invite friends".
2. This click opens up a facebook friend selector widget (something like the multi-friend-selector), and the user selects friends from it.
3. The selected friends are POST-ed to a custom URL using an Ajax call and the selector widget goes away.

I'm able to do steps 1 and 2 using a fb:request-form and fb:multi-friend-selector. However, by default that开发者_JAVA技巧 posts to facebook and redirects the page. Is there a way to simply retrieve the UIDs of the selected users and then post them to a custom URL instead?

This topic is muddy water right now.

The current way is to implement your custom URL with an fb:req-choice in the content attribute of your fb:request-form as described here.

But as you can clearly see on that page - they are soon deprecating that element and changing how requests/invites work in general. So you can implement it like this for now, but will probably have to change it when they release more details about the new system.