MP3-Upload

Pretty cool Plug-In! Wow! That´s what I need!
But in my case, the user have to upload 4 JPG´s and 1 MP3.
The upload with the JPG´s works fine, but how can I realize it, that a MP3-File upload to the post, too?
If I upload it like the JPG´s, it´s missing in the post.
What can I do?

http://wordpress.org/extend/plugins/user-submitted-posts/