Press New

Press Advanced

Add   X-Spam-Suspected-by-Msen-because-of-Envelope
Press Add
Add   X-Spam-Suspected-by-Msen-because-of-Header
Press Add
Press OK


Give the filter a name
Click Match any
Select Contains
Enter a [
Click New Folder and add a spam folder
Press OK

Click Log Filter Use
Press OK

And now you should have a filter that will take all mail that Msen suspects and marks as spam, and place it into is own "spam" folder under the inbox.