Adding settings with form to my extension - what am I missing?
Perhaps another example will help you along:

The Form:
https://github.com/jake-mw/CDNTaxReceipts/blob/master/CRM/Cdntaxreceipts/Form/Settings.php

And some of the settings are retrieved here:
https://github.com/jake-mw/CDNTaxReceipts/blob/master/cdntaxreceipts.functions.inc#L73