you can add up to 4 custom charsets (like on cli) but seperated in maskfile by , and also you can combine them with build in e.g.
charset 1 = abdehimnoz
charset 2 = 123
abdehimnoz,123,?1?1?1?1?1?1?1?1?1?2?2?2?a
charset 1 = abdehimnoz
charset 2 = 123
abdehimnoz,123,?1?1?1?1?1?1?1?1?1?2?2?2?a