Yes I had it working with Python games, I added the little bit to the bash script to switch the sound without resorting to the command line. If I remember correctly only the jewel swapping game has sound, the others are silent. You can look at the script that runs python games and you will see what commands are used to switch the sound.
Different programs have different ways to switch the sound output, e.g. for OMXPlayer you have to specify the output in the command and it takes no notice of the command in the python-games switch. Did you have HDMI sound working for Scratch in the Debian Squeeze release, there is a report of it not working in Squeezy here https://github.com/asb/spindle/issues/68
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