Generate PDF file in backend, and "send" it to SAP Gateway

Hi

We want to generate PDF file in SAP backend, and when it is done, we want to send it via SAP Gateway.

A user will push a button, and it will create a report/pdf file with data from backend.

When the pdf file is done, we want to send it back to the user via SAP Gateway.

Anyone who can guide me?

Thanks

Lars