Gotta a Blackberry 6750 running 4.0 on Bell, using BWC. I have a colleague that has the same thing with a Blackberry 7xxx on Telus using BWC.
An e-mail message gets sent in HTML with an attachment...any kind of attachment, and it magically hides the text from the message.
in the message it says:

[2 Attachments]
-------------------------
application: multipart/mixed
application: attachment.doc (30k)

I hit the menu to open attachment, and it says there's only one attachment, and won't let me see the text from the message.

I don't remember this happening when I had 3.6 on my Blackberry, but it happens all of the time with 4.0

Any ideas?