Breaker Interlock question

I have a Challenger sevice panel outside with a Main qfp-150-2 pole Breaker and it has 4 breaker bus bars below. Two slots will hold a double pole 30 AMP breaker to backfeed the panel from a generator. I am using an interlock kit to prevent the main and Generator breaker from both being on at the same time. The problem I am having is that there is a tab to fasten a pad lock on the right hand side of the toggle on the main breaker that is in the way of the interlock. Can this tab be remove (cut off) or is that a code violation of the NEC. I live in South Florida.