Thankyou for your reply KRK.
I've thought about that way to deal with it, but It's not a good way, since it always depends on what kind of paper that is used during the printout A4 or A3 (yes, they do use different types in this case).
The SY-PAGNO get's its value just before printing, since its dependent on if I use a pre-page or not. And from the printout screen I'm also able to print "page X to Y". So in the background there should be some system parameter that contains the total amount of pages (dependent on the type of format that is selected during printout).
Another way around would be to use Sapscript instead, there I think there is a system-parameter for the total amount of pages.
But, again, the best way would be if I in a correct way could put a parameter with the total amount of pages, that I can rely on.
Best reg
Henrik