re:
Given that you should have copied the .xap files onto the root directory of your SD card, you may have to wait for a couple of minutes or so after restarting your phone for the apps to appear. My experience with the HTC 8S was exactly the same - .xap files did not appear after restarting the phone... but I came back to the store 5-15 minutes later and the apps appeared in the store under "SD Card". My guess is that the phone is recognizing/authenticating the .xap files first before you're allowed to install the apps. This may include verifying the version or license to the apps online, so you may need to be connected to the internet.
These are just my GUESSES. Try coming back to the store several minutes after restarting your phone and see if "SD Card" appears in it.