call a filter manually

[Chaos Master]

Hi I'm trying to understand the following behavior.

When I print a file with Adobe Acrobat and take the raw unfiltered output it starts something like this:
[code]
%!PS-Adobe-3.1
%ADO_DSC_Encoding: MacOS Roman
%%Title: pdftest.pdf
%%Creator: Adobe Acrobat 9.3.3
%%For: chaosmaster
...
[/code]

If I set up a printer with the generic postscript driver (GENPS.PPD, not the foomatic one), the output is something like this:

[code]
%!PS-Adobe-3.0
%%LanguageLevel: 2
%%DocumentSuppliedResources: (atend)
%%DocumentMedia: plain 595 842 0 () ()
%%For: (chaosmaster)
%%Title: (A9ROdslk6S)
%RBINumCopies: 1
...
[/code]

Now, when i manually pass the raw file to the pstops filter it starts something like this:
[code]
%!PS-Adobe-3.0
%ADO_DSC_Encoding: MacOS Roman
%%Title: pdftest.pdf
%%Creator: Adobe Acrobat 9.3.3
%%For: chaosmaster
[/code]

So the first line changed from "%!PS-Adobe-3.1" to "%!PS-Adobe-3.0" but y did the filter not change the title?

How can I make it change the title?

Thanks in advance,

Chaos