I\'m trying to merge 2 PDF, one on my server (not dynamically generated) and one generated just before the merge and not saved anywhere on the server (I just want my client
Have you tried merging them using the PDF toolkit?
Merging multiple PDFs with it can be achieved using :
pdftk 1.pdf 2.pdf 3.pdf cat output 123.pdf
123.pdf will be the resulting PDF. You can temporarily store the resulting PDF on the server, send it to the browser and remove it when it's no longer needed.