Microsoft Power Automate | Working with signed documents

Hi, 

I have a workflow that gets all invoices (either from Outlook or from OneDrive) my company receives and based on certain conditions it adds and extra page to the invoice indicating the cost center, and forwards the updated pdf to the accountant. In the past half year the number of electronically signed pdfs increased a lot and the Adobe pdf handler fails when trying to add a page to these pdfs. I understand that these are protected files for a reason and they can't be edited, yet has anyone any suggestion how to solve this problem? I tried to copy into a new pdf and add the info to that, or export the pages to images, creaete a new pdf from that, but unfortunately I did not succedd. Any help is appreciated. 

Thanks,

András