I've added a group of settings as a new tab on the "General and Miscellaneous Settings " admin page.
They are saving and retrieving correctly.
Now I need to access them from the CheckoutController, where I have added a call to a custom class that needs this info (was hard coded or in web.config while testing of this class) to generate an EDI 850 output file.
I have the "Order" object, and I've fully tested the rest of the code in the addon class. It works great, but I want to change it to use actual settings.