How to add a page with static content at a specific position?

Hello,

For a couple of days I try to figure out how to solve this problem:

I have to generate a PDF from a docbook-source (generated with 
AsciiDoctor). The transformation itself works like a charm. But I have 
to insert some static content as fourth page in the resulting pdf. I 
think that should be pretty easy, but I did not manage to find a way to 
do this.

Any help is highly appreciated!

Christian