angkeg armor & thieves

I have a fighter/thief character and have discovered that if I want to do thiefly skills (other than looking for traps) I have to take the dang armor off! Is this because thieves can't wear the armor? A bug? It's annoying and a time waster as far as I'm concerned. :(

Sorry if this has been discussed, I couldn't find anything other than a bug report on the armor. Thanks.