getting info from a nested message

Sorry for asking a "how-to", but I've looked through the modules, 
documentation, and the mailing list and can't quite figure this out.

I have nested messages in the form "message/rfc822". I want to grab the 
nested message AS A MESSAGE so I can query the sender, extract the 
subject, and delete artificial headers before processing the message 
(into a word parser). How do I do this?

This is what I have:

    my $part   = $message->body->part(1); #the first part is always the 
nested message
    if($part->isNested) # just a test to make sure Mail::Box interprets 
this correctly
    {
       #this is a nested part...
       my $nestedmessage = ????????????
    }

Now, how do I turn that $part into a message so I can work with it?

Thanks for any help.

Mike