I haven't come across a setting that automatically strips attachments from the copies of sent mail as they are saved, is that what you had in mind? There is an add-on called Attachment Extractor which looks as though you could use it to remove attachments after the copies are saved. I haven't used it myself but it might be worth a look.

Thanks Fella,

What I really want to do is keep the message but automatically delete the attachment. I send a lot of reports out and already have the files on my 'pooter so don't need to save the file in the sent box although I do need proof of sending the e-mail.

Unfortunately, doesn't look like the attachment extractor would serve this function.

mikehatton said

Unfortunately, doesn't look like the attachment extractor would serve this function.

Then I would say you are stuck.