mailcap question

["Wilkinson, Alex" <alex.wilkinson@xxxxxxxxxxxxxxxxxxx>]

Hi all,

I have received a Microsoft Excel spreadsheet. Typically I open these via
gnumeric. 

I have the following in my mailcap file:

        application/excel;  gnumeric %s; test=test -n "$DISPLAY";

And the following in my mime-types file:

        application/excel          xls

The problem:

The email I have received is definitely an excel spreadsheet but has the
mime-type of: 

         application/octet-stream;

Question: Why doesn't mutt recognize the mime type to be of type 
application/excel ?

          Correct me if I'm wrong, but I thought that a message is assigned a
          particular MIME-type based upon what is in your mime-type file.

          e.g application/excel xls

          So anything with the extension xls will be assigned the MIME-type
          of application/excel. Is this correct ?

 - aW