cocos2d-iphone - Cocos2D: Best way to display text from font atlas?

Question

Based on the use CCDirector makes of CCLabelAtlas, I tried the following:

scoreLabel = [[CCLabelAtlas alloc]  initWithString:@"0123456789" charMapFile:@"fps_images.png" itemWidth:8 itemHeight:12 startCharMap:'.'];
[scoreLabel setPosition:ccp(200, 200)];
[self addChild:scoreLabel];

I must be missing something as nothing displays. I'm using the basic .png that's supplied with Cocos2D.

What am I missing? Thanks!