I have done something similar for LPG stations. In my TYP file there is an icon for a standard fuel station. It's a miniature gas pump like the one GArmin has built in. I have another icon that contains the characters LPG (written vertically) to the left of a transparent section that is large enough to allow the pump icon to be visible too. This allows me to use various other custom fuel icons on my maps and merely overlay the LPG icon when needed. If you still have my TYP file you can check out the appearance of those icons yourself. I don't think it matters if you use track up or north up but Gerd will know the answer to that one. I can't recall how my display works as I almost never use track up.