Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!ames!sdcsvax!ucbvax!JPNKEKVM.BITNET!FRY
From: FRY@JPNKEKVM.BITNET (Alan Fry)
Newsgroups: comp.os.vms
Subject: RE: DECNET Mail <-> SMTP
Message-ID: <8705301135.AA14060@ucbvax.Berkeley.EDU>
Date: Sat, 30-May-87 07:35:57 EDT
Article-I.D.: ucbvax.8705301135.AA14060
Posted: Sat May 30 07:35:57 1987
Date-Received: Sun, 31-May-87 19:45:34 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
Lines: 2

Have you tried exclamation mark (!) to replace ::?  I seem to remember this
used by ARPA to specify path for mail.