On a Droid 4, when I have Smart Keyboard Pro active and enabled for the physical keyboard I have two problems.
1. I cannot type symbols using the physical keyboard.
2. The caps lock does not work at all
Note that the Droid 4 has a different keyboard with no alt key. It works like a computer keyboard (for instance, press shift 2 to get the @ sign). I do not have the same problem on a Droid 3.