That may be a tricky one....if you could get your hands on some more plastic, try to melt it together, like a plastic weld. I don't think glue or anything would work as I think that would break. Do you have a picture of where it is broke (like did the tab break clean off? or did it split thru just where the bold goes)? Worst case, use some rivets and make a little metal mount and rivet to your plastics.