Right-enable a pdf edited by a server process

Hi,

I use since few years a process to collect FDF data from a pdf form filled inside a Reader, that are process on a web sever (with FDFMerge) and return a pdf with the data in it for saving locally.

Now, I want to use the Reader-enable functionnality of Acrobat 8 to allow users saving pdf fill form straight from their Reader.
BUT I want also to keep my functionnality of sending by e-mail (through the server process) a pdf file with filling fields that keep the reader-enable functionnality.

It seems that the FDFMerge process (fill the fields with the data collected and send back the pdf) doesn't keep the pdf Reader-enable.

So is there a solution to programmatically keep reader-enable a PDF file on a server (without JBoss or WebSphere because on a IIS server .NET).

Pleasehelp me because we migrate some documents and have no solution for that.

Thanks
Florent.