You can not specify a structure field key path using Objective-C 2.0 properties. This will not work:

myLayer.transform.rotation.x=0;

Instead you must use setValue:forKeyPath: or valueForKeyPath: as shown below:

[myLayer setValue:[NSNumber numberWithInt:0] forKeyPath:@"transform.rotation.x"];

brrrrrr.

- (id)valueForKey:(NSString *)key

• (void)setValue:(id)value forKey:(NSString *)key

... NSKeyValueCoding Protocol Reference