I finally managed to have a readable set of numbers for the digital clock, even if am sure there is something else to learn about their strange mask mechanism. If you like my theme feel free to download and install it on your 6600. Give feedback!
You can see a preview at http://www.allaboutsymbian.com/forum/attachment.php?s=&postid=148220 .
I have already started to work on my next theme, dedicated to Ganesh, the Indian god with the elephant head, "remover of obstacles".
Enjoy!
Giacecco