I can't seem to find any possibility to have an indication for people, who have set themselves as "away", in the user list of a channel. (like several other IRC-clients do by writing that nick(s) italic)
Even if one wanted to script something like that the user list does not provide the away-status, afaik.

If there is no solution possible on the current code-base I'd like to requeust either the implementation of such a feature by writing nicks in italic or another color or $users-choice-here
or the implementation of an away-flag which can be evaluated programatically by mIRC's scripting feature.

If I'm completely overseeing an already existing possibility, feel free to point me to the correct direction.