The auto-away (idle) feature is a feature of MSN Messenger itself and there is nothing plus can change about that. If u don't want ur status to change to away(idle) u gotta turn it of Tools > options >personal tab .. uncheck show me as "Away" when i'm inactive for .. mins.
Auto Away features will always override ur current status cuz u tell it to do so (it's whats its supposed to do). Same goes for the auto away in plus.
If u don't want that simply turn it off and choose ur status manually. U want it when not in personalized status? Simply turn that option on again when ur not using personal status
Yes, there is another thread bout this. I posted in it, its this one:
http://shoutbox.menthix.net/showthread.php?tid=26353