Create the same message from within SQWebmail (or any other
mime-compatible client) and compare the headers and content.
I am sure it will work fine. It does work for most of the other stuff.
Content-Type: application/pdf; name="myfile.pdf"
I dont know why SQWebmail shows any type of application/*
as plain text, if the message is formatted as above you get
a link for downloading, types of image/* could even be viewed.
I was trying to point out, that there might be a problem within SQWebmail,
with regards to the MIME handling. I already worked around it, but I am not
sure, it won't hunt me from a different angle.