How to subclass AtlasSpriteManager in Cocos2d?

I need to create some compound sprites that will all move and rotate together. Since it's possible to change the position and rotation of an AtlasSpriteManager I've been trying to subclass so I can create a bunch of shortcuts like

CompoundSprite *cSprite = [CompoundSprite spriteManagerWithFile:@"sprites.png"];
[cSprite makeComplexSprite];

internally, it looks a little like this

-(void)makeComplexSprite
{
        AtlasSprite *sp1 = [[AtlasSprite spriteWithRect:CGRectMake(0, 0, 64, 64)       
                             spriteManager:self] retain];
        AtlasSprite *sp2 = [[AtlasSprite spriteWithRect:CGRectMake(0, 0, 64, 64) 
                             spriteManager:self] retain];

    [self addChild:sp1];
    [self addChild:sp2];


    [sp1 setPosition:CGPointMake(0,0)];
    [sp2 setPosition:CGPointMake(64,0)];

}

However, when I run the applications, It crashes with the following exception

Terminating app due to uncaught exception 'NSInvalidArgumentException', 
reason: '*** -[AtlasSpriteManager makeComplexSprite]: unrecognized selector sent to 
instance 0x107e1c0

Also, if I remove all the code inside 'MakeComplexSprite' and make it do nothing, I also get the same problem.

It's looking like AtlasSpriteManager just doesn't like to be sub classed. Is this the case? If so, why, and how could I work around it?

UPDATE:

I've found a workaround, by creating an NSObject that contains an atlasSpriteManager. It does the trick, but I would still like to subclass AtlasSpriteManager if possible. I appear to be implementing this exaclty as you describe. I'm creating an instance like this

CompoundSprite *cSprite = [CompoundSprite spriteManagerWithFile:@"file.png"]; 
[cSprite makeBox]; 

which... now I think about it, means that cSprite is still an AtlasSpriteManager since that's what is being returned. hmmmm. Ho do I change that?

Implement your own spriteManagerWithFile: or compoundSpriteWithFile: in CompoundSprite, which will return an instance of CompoundSprite.

Edit:

Or, you can do something like

[[ComplexSprite alloc] makeComplexSprite];

But then you need to do the 'spriteManagerWithFile:' part also. Like:

-(id)makeComplexSpriteWithFile:(NSString*)file
{
    if (! (self = [super initWithSpriteManager:..capacity:..]))
       return nil;

    // do your ComplexSprite specific initializing here..

    return self;
}