You can add a ?help command to your server (its not a biller thing) by editing server.ini, AlertCommand setting (in the Misc setting).
The source to catid's biller can be found on http://catid.ssihosting.com: http://catid.ssihosting.com/files/ssb2.zip . The source files are inside the archive in a zip called 'ssb2_src.zip'.
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