It's acceptable. You just have to make it sleeveless, and make sure the front is open enough that it doesn't cover up your armor. That generally means you'll have to retailor the lapels, which really isn't difficult even if you don't have much sewing experience. Ask someone more local for hands-on help if you need to. Your clan's Ruus'alor should be available, or if not, can point you in the right direction to get whatever you need.