Bookmark to PDF

I want to add a bookmark to page one of an existing PDF.
How to do that with PHP-code?
Please give an example.

How to make this working:

I have in a folder (c:/documents/) a document called example01.pdf and want to add a bookmark to it.

sc_include_lib(‘tcpdf’);
$var_bookmark = “Chapter1”;
$pdf->Bookmark($var_bookmark’, 0, 0, ‘’, ‘B’, array(128, 0, 255), -1, ‘%c:/documents/example01.pdf’);

What’s is the meanng of the parameters in $pdf->Bookmark()
And how to get this working?

Please help. Its is very important for me…

Regards Bert

Somewhere I read that it is impossible to do this with the tcpdf. You have to import an existing PDF and that function is under construction.
Some other way…Somebody?