Half of my UITabbar not working

Question

The bottom half of my UITabbar is not responding. I have found more people with the problem, but no solutions.

I think the problem may be caused by me not using the tabbar for a fullscreen application, but only a part of the screen (320*380 on iPhone). I am, however, using a custom UITabbarController. This is after the constructor for my UITabbarController subclass:

    -(void)addCustomElements
{
    UIImageView *tabBarBackground = [[UIImageView alloc] initWithFrame:CGRectMake(0, 306, 320, 74)];
    [tabBarBackground setImage:[UIImage imageNamed:@"Tab Bottom.png"]];
    [self.view addSubview:tabBarBackground];

    UIImage *buttonImage = [UIImage imageNamed:@"Places Tab.png"];
    UIImage *selectedImage = [UIImage imageNamed:@"Places Tab Selected.png"];

    btn1 = [UIButton buttonWithType:UIButtonTypeCustom];
    btn1.frame = CGRectMake(0, self.view.frame.size.height-42, 160, 44);
    [btn1 setImage:buttonImage forState:UIControlStateNormal];
    [btn1 setImage:selectedImage forState:UIControlStateSelected];
    [btn1 setTag:0];
    [btn1 setSelected:YES];

    buttonImage = [UIImage imageNamed:@"Map Tab.png"];
    selectedImage = [UIImage imageNamed:@"Map Tab Selected.png"];
    btn2 = [UIButton buttonWithType:UIButtonTypeCustom];
    btn2.frame = CGRectMake(160, self.view.frame.size.height-42, 160, 44);
    [btn2 setImage:buttonImage forState:UIControlStateNormal];
    [btn2 setImage:selectedImage forState:UIControlStateSelected];
    [btn2 setTag:1];

    [self.view addSubview:btn1];
    [self.view addSubview:btn2];

    [btn1 addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];
    [btn2 addTarget:self action:@selector(buttonClicked:) forControlEvents:UIControlEventTouchUpInside];      
  }

And i create it like this:

tabBarController = [[CustomTabbar alloc]init];
        tabBarController.view.frame=CGRectMake(0, 0, 320, 380);
        [tabBarController viewDidAppear:NO];
        mapsView = [[MapView alloc]init];
        placesView = [[FavoritesList alloc]init];
            //Suggestions from another forum (didn't work):
        //[mapsView setWantsFullScreenLayout:YES];
        //[placesView setWantsFullScreenLayout:YES];

        mapsView.title=@"Maps";
        placesView.title=@"Places";

        placesView.mapView=mapsView;
        mapsView.favorites=placesView;

        NSArray *controllers = [NSArray arrayWithObjects:placesView, mapsView, nil];
        [tabBarController setViewControllers:controllers];

        [self addSubview:tabBarController.view];

Does someone know a fix for that?