[andrewas]

You can use them, but you incurr the penalties as though you didnt have any dual or ambidexterity feats as well. Which is, -6 primary, -10 in the offhand. There may be situations where this is worth it, specificaly when the target has very low AC and can be hit reliably even with that penalty. But in the main, if you can hit something that easily its probably not worth putting on extra armour in the first place.