What are the correct settings for invitations, open graph and app store?

Question

The situation is this:

• I want to use the facebook sdk to let users of my iOS app to send invitations to their facebook friends. I want those invitations to direct the invited facebook user to the app's app store page. Facebook invitations work just fine but I am failing to find the proper documentation in order to direct the invited user to a specific location when they click on the invitation. Now they are sent to *siteurl/?request_ids=1234567890&ref=notif&app_request_type=user_to_user*, where siteurl is the Site URL I set on the facebook app settings page (under Website with Facebook login). I have tried including a bunch of things to the params dictionary, such as redirect uri, target url, link, href, but nothing seems to change where the users are directed to.

• Then, I also want to implement some open graph functionality so the users of the app can post certain things they did in the app as actions on their facebook wall. In order to do that, I need to change the Site URL to the server that my open graph pages are hosted.

• I am also letting users log in with their facebook accounts if that's of any importance.

I have failed to find any proper documentation regarding what is what, what I can include in the params dictionary and how I can control the behavior of the invitations that are sent and I could really use some help in order to get things right. Note that the app is not in the app store yet so I don't have store ids.

That's the code I have for the facebook invitations:

// FACEBOOK INVITATION REQUEST
-(void)sendFBInvitationRequest
{    
    NSMutableDictionary *params = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                                   @"Come join me!",  @"message",
                                   @"http://www.stackoverflow.com", @"redirect_uri",
                                   nil];

    AppDelegate *app_delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];

    // MAKE SURE THE USER IS LOGGED IN
    [app_delegate openFBSessionWithAllowLoginUI:YES];

    NSLog(@"YOU SHOULD SEE THE DIALOG NOW!");
    // AND THEN SEND THE FB REQUEST
    [app_delegate.facebook dialog:@"apprequests"
                        andParams:params
                      andDelegate:self];
    NSLog(@"SENDING REQUEST");
    NSLog(@"%@", [params description]); 
}