Right, Super Text Mesh has a custom material viewer for editing material properties right in the editor (The code for this is within STMCustomInspectorTools.cs) but that's not needed to edit the material properties, you can edit it as if it's a normal material! (By clicking on the created material in the project window, and editing the properties in Unity's inspector)
I'll take my own try at it and email you that, but it sounds like you've basically got it! For the record, I wasn't going to edit the inspector code to get this working, myself... If I'm happy enough with the implementation, I may add it as a standard feature to the Ultra shader, but I'll have to test for performance efficiency