Based on the Feature suggestion over there: http://forums.mirc.com/ubbthreads.php?ubb=showflat&Number=233134
this thread shall reflect the attempt to implement the functionality on the script side of the client.
Just to summarize the idea: The goal is to have an indication for people, who have set themselves as "away" (primarily in the user list of a channel but having the same functionality in the notify list or use the results for the notify list where applicable might be an idea, too) like several other IRC-clients do by writing that nick(s) italic. (instead of italic another color or similar would also do the job, of course)
The user list / address list does not provide the away-status for now, so this would need to be worked around and completely be written from scratch, it seems.
As a beginning it is suggested to use the /WHO command on a regular basis to determine the status of the user. (see paragraph "The reply" in http://www.irchelp.org/irchelp/misc/ccosmos.html#Heading513
which lists the flag H/G (Here or Gone) in the /WHO-response, indicating if the nick is set /away or not)
As noted the /WHO command would need to be used thoughtfully to not cause issues when being used on large channels. (sidenote: I personally am not completely aware of how to prevent bad consequences of usage on large channels, if responses get too big, yet)