We have a small number of users who digitally sign (but don't encrypt) their email. When they send attachments, it usually works fine. However, when the recipient is using Outlook Mobile, all attachments disappear for them leaving behind only the S/MIME p7m file. Is this a known problem, and is there a solution besides not signing the message?
What we suspect so far is that the sending client is bundling the other attachments inside the p7m, ignoring the facts that 1) the message is signed but not encrypted, and 2) some clients might not be able to extract them again.
