Licensing PDFs

Hi,

We want to license some of our documents for electronic use, we thought this
would be done best as PDFs. However, the problem we have is that we want the
user to be able to edit the documents for their own purposes - as such they will
need to be able to save this version but we do not want them to be able to save
the original document. We also want to limit the number of documents they can
create from our template. For example, they may pay for 10 licenses so we would
want the document to expire after 10 copies had been produced from the
template.

Can anyone offer any advice on how to go about this or if it is even possible?

Thanks,