Watermark Printouts (Mac OS X)

[Hubi Schulze]

Hello,

after reading the existing thread about watermarks I know that is possible, but not exactly how to get this work.
I also tried to edit my printers ppd as described here:
http://www.cups.org/documentation.php/spec-ppd.html
but it did not work at all...

So could anyone of you give me something like a step by step guide for adding a watermark to every printjob of a printer using cups (on a mac)?
Would be charming and a great help for a lot of Mac-Users out there =)!