In Photoshop or Graphic Converter, you can customize this clock face file. Remember that the face is transparent outside the circle. If you cut/paste artwork and flatten, this will be a problem. Instead, when I used Photoshop, I merged visible of the layer with the bottom one (the original Clock02.tif). Voila! I had my custom clockface back. I saved the file on the desktop, (Photoshop would not allow a system-level save). Then I replaced the (you did back it up, right!?) original Clock02.tif with the modified file (keep the name the same, obviously) after it asked for authentication. I logged out and back, and there was my clock. Hope this helps...
[robg adds: I played around with this, and it works -- though my lack of Photoshop skills probably meant it took more time than it should have!]

