Comment 37 for bug 303140

Just stumbled over this bug while searching the internet for a solution to remove attachments from signed mails.
I'm aware of the implication that the signature would no longer be valid. Since I'm also signing all of my outgoing mails and my account is constantly growing I'd love to see a solution for this problem.
Has this bug never been addressed since its submission over 7 years ago? Or is there already another solution I didn't find?