I have the following code:

-(void)showLeaderboard {

GKLeaderboardViewController *leaderboardController = [[GKLeaderboardViewController alloc] init];
if (leaderboardController != NULL)
{
    leaderboardController.timeScope = GKLeaderboardTimeScopeAllTime;
    leaderboardController.leaderboardDelegate = self;
    [self presentModalViewController: leaderboardController animated: YES];
}

[leaderboardController release];

}

Which I am trying to use to make my leader-board pop up. The issue is cocos2d will not allow me to use the line:

        [self presentModalViewController: leaderboardController animated: YES];

How do I fix this?

Thanks

PS I am using cocos2d