How to get the address "A!u at B" to work

[Ami Motro]

Hello Unix experts,

Assume two 3B2/Sys V 3.2.2.
Machine A is networked with Wollongong TCP/IP.
Machine B is connected to machine A via uucp.

Sending mail from the world to user on B is possible with addresses like 
	user%B.uucp at A
(sendmail on machine A handles things properly).

However, attempting mail from B to the world with addresses like 
	A!user at ...
doesn't work.  The uucp protocol invokes rmail on machine A which cannot
handle the internet address user at ....

There must be a clean solution to this (e.g., somehow invoke sendmail through
the uucp protocol).  Advice would be greatly appreciated!

Ami Motro
ami at usc