I need to show some glass panel doors in a Formica color. I tried copying a .jpg from the Formica directory into the "Finishes" directory under doors/Conestoga/finishes/hard maple. The new color showed up in the door editor, but would not display when selected.
Only finishes that are included in the Conestoga folder can be used. You could rename one of the existing finishes and give your file the same name as the existing finish you renamed.
You could also create a temporary display cube and give it the color you want then use Texture Match to change the color of the door.
Glad it worked for you. I typically use the display cube method as well. If I need to show something in several colors, I add a display cube for each color and do a texture match to change the cabinets. It isn't perfect but it is fast.