I just bought a Blackhawk level 1 retention holster for my ISSC M22 off ebay. According to everything I read online, the M22 fits the Glock 21/37 holsters as the M22 made by ISSC is pretty much a Glock Clone for the way its made. The holster I bought is made for a Glock 20/21//37. The M22 does fit the holster, however it does not latch in to the trigger guard safety. I've loosened and tightened the trigger tension screw but no luck. The gun fits in the holster all the way just wont lock in place. Any idea? I'd hate to return the holster.