Can't get the uids that back from post of fb:request-form on MVC

Question

I'm tring to get the uids that user selected at the but always back null the ids.

 <fb:request-form action="http://myapp/controller/index?id=<apid>&sk=<secret>"
        method="POST" invite="false" type="Invite" content="<fb:req-choice url='http://myapp/controller/index?id=<apid>&sk=<secret>' label='invite' />">
    <fb:multi-friend-selector showborder="false" bypass="cancel"  cols=3  actiontext="Invite example"/>
    </fb:request-form>

After user invite, redirect to my action.

[HttpPost]
    public ActionResult Index(long[] ids)
    {
        return null;

    }

the ids always return null.

Answer 1

why on gods green earth are you transmiting your secret key in the form action ?

And to answer your question, you have to set invite="true" to get the ID's AFAIR. But be warned, the whole process has changed, and is using requests 2.0 but with very strict limitations. see http://bugs.developers.facebook.net/show_bug.cgi?id=17113 for details.

EDIT: fixed wrong bug id