You can add anyting you want to the part painter...
Format>Style>Style Types - Face Style> New.
If you intend using the new styles on other items, make sure you edit the templates you use when you create the style. Using the Organise button you can add the new styles to old drawings too, though sometimes it crashes SE.
I've created 20 styles, all with a prefix, so the Engineers know to use them. All the standard styles I've selected each one and clicked modify and added a [ and a ] to the start and finish of the filename to move them to the end of the list.
I save all my styles into an external file via the organizer. Templates get overwritten, files get saved over, so that's why I created a file just to store all the styles and I keep it in a safe network folder that gets backed up.
Anytime I find a new texture, bump map, color definition, or any other style, I make sure I add it to my master style part.
