Watermark PDF files

Heaven.
Wondering if there is a way to watermark a member details when he downloads a PDF file that is located in s2Member Files folder i am aware of a plugin that can do this in his own folder, however as i have s2Member Pro i don’t want to install it and not sure it is secure enough.
I have searched on google and found one unanswered topic on s2Member Site that is why i decide to ask here.
Thank you for any inputs on this matter.

s2Member does not offer integration with such a feature.

If you are happy with a generic watermark, you can just make that part of the PDF file yourself.

If, instead, you want a watermark that is specific to the user, you will need to use another plugin. I don’t know whether such a plugin will work if the file is stored in an s2Member-protected folder.

Yes it seems i will have to install that plugin.
Thanks.