How do I specify curly braces in the argument of \maple*?

I tried them as single characters, then they are gone after the Latex run.

When I try \{ ... \} instead, then the latex2qu run gets a stack overflow.

I can write square brackets instead and replace them in the .qu file, but that's very inconvenient.

Or is it a general necessity when you write your questions using Latex, that you have to edit the .qu file for similar shortcomings?