forwarding MIME encocded attachments

I have the following recipie in use to forward a copy of all mail
received, to another account with the subject changed to have [cadamin]
prepended to the subject. Problem is, if email has attachments I'm just
getting a message with the subject only.

How can I modify the recipie to forward all attachments also.

MSGSUBJECT=`/hwtools/bin/formail -zxSubject:`
0 h c
| $MAILX -s "[cadadmin]$MSGSUBJECT" gcasey(_at_)somehwere(_dot_)in(_dot_)world