Post on FB friends wall in iOS using SLRequest and Device Settings Credentials

Question

I am developing an iOS app in which I have to invite to user Facebook Friends to join the app. I am using Social Framework to do so. I have successfully posted on FB wall of logged in user but there is a problem in the message which I posted. the message says that "User has shared a link via sample app. Pleas join this awesome app.". I want the message:

"User -> Friend Please join this awesome app.".

I want it like when it appears when we write on Friend FB Wall.

I have added the "to" parameter in which I am passing the friend's unique FB id. But it's not working.

Below is the code which I am using for this:

[accountStore requestAccessToAccountsWithType:facebookAccountType options:dict completion:^(BOOL granted, NSError *error)
{
    if (granted)
    {
       __block ACAccount * facebookAccount;



   NSDictionary *options = @{ ACFacebookAppIdKey: **FBAPPID**, ACFacebookPermissionsKey: permissions, @"ACFacebookAudienceKey": ACFacebookAudienceFriends };

   [accountStore requestAccessToAccountsWithType:facebookAccountType options:options completion:^(BOOL granted, NSError *error)
   {
      if (granted)
     {
         NSArray *accounts = [accountStore accountsWithAccountType:facebookAccountType];
                         facebookAccount = [accounts lastObject];

        NSURL *postURL = [NSURL URLWithString:@"https://graph.facebook.com/me/feed"];

            NSMutableDictionary *postDict = [NSMutableDictionary dictionaryWithObjectsAndKeys:
**FRIENDID**, @"to",**FRIENDNAME**, @"name",@"Testing of app.", @"caption", @"please join this awesome app.", @"message", nil];

        SLRequest *postToMyWall = [SLRequest requestForServiceType:SLServiceTypeFacebook requestMethod:SLRequestMethodPOST URL:postURL parameters:postDict];
                         [postToMyWall setAccount:facebookAccount];

                         [postToMyWall performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error)
                          {
                              if (error) {

                              }

                              else
                              {
                                  NSLog(@"Post successful");
                                  NSString *dataString = [[NSString alloc] initWithData:responseData encoding:NSStringEncodingConversionAllowLossy];
                                  NSLog(@"Response Data: %@", dataString);

                                  [self performSelectorOnMainThread:@selector(postSuccess) withObject:nil waitUntilDone:NO];
                              }
                          }];
                     }
                     else
                     {
                         NSLog(@"rfc");
                     }
                 }];


 }

   else
            {
                [self performSelectorOnMainThread:@selector(showerrorAlert:) withObject:error waitUntilDone:NO];
            }
        }];

Please if anyone can give a solution for this. I can use Facebook Framework also but I need to authorize the user and fetch his/her friend list using the credentials stored in iPhone Device Settings. So if you have an alternate solution then please let me know.