save modified email attachment in received email

[Dexter <dexter@madalbal.sk>]

Hi,
do somebody know, if it`s posible to modify email attachment (document)
and save it in the same received email? This mean, next time you open
the same email, attachment will stay modified.
I know, it is posible on MS Outlook through IMAP. I wass not able to do
it with other program.
   Dexter