the Homeline series and the QO series use different methods of attachment to the bus and therefore will not work interchangably. If you have one of each, look at the prongs used to contact the bus and you will see a difference.
with that said, do you realize it is not legal to install a breaker in a panel for which it is not UL listed. Square D, the last I knew, did not seek UL listing to place any of their breakers in any other manufacturers panels. Some other manufacturers have obtained UL listing for interchangeability into Square D panels though. You would have to check the specific UL listing for each breaker and panel or the manufacturer to determine if they are legal to interchange.