Hi,
I've got problems with the following combination:
3 Mail Accounts (2 x IMAP, 1 x Exchange).
I don't sign mails on the IMAP-accounts, but on the Exchange one, when sending mails from other devices (with Outlook or Thunderbird), as I'm still waiting for the feature in Aquamail.
Interestingly enough, Aquamail does no longer display attachments on the Exchange account, when the mail has been signed (on another device).
So when I look at my sent mails, I can only the .p7m-file as an attachment, but for example the .pdf-file I sent is missing.
On incoming mails, which are not signed, the attachments show up as expected.
Looks like: If the mail has been signed, only the signature file ist displayed as an attachment (and not yet interpreted).
Maybe you could have a look into this.