Non-US Keyboard and CMD + SHIFT + 7

Solution 1:

The easiest option would be to just change the help menu shortcut:

You could use KeyRemap4MacBook to change ⇧⌘7 to ⇧⌘ß:

<autogen>__KeyToKey__ KeyCode::KEY_7, VK_SHIFT | VK_COMMAND, KeyCode::MINUS, ModifierFlag::SHIFT_L, ModifierFlag::COMMAND_L</autogen>

You can also configure shortcuts using a shell script like this:

defaults write -g NSUserKeyEquivalents '{
"Comment Selection" = "@-"; // cmd-minus
"Toggle Comment" = "@-";
}'

In TextMate the shortcuts for bundle items have precedence though.