Caution!  The following is untested, speculative and personal opinion!

On an NT system (and any other I suspect) it is possible to run the
"DSMADMC.EXE -consolemode" command.  This results in a window which receive
many, and particularly tape mount, messages.  If you truly only want tape
mount messages use the "-mount" flag instead of "-consolemode".  Most, if
not all, commands can have their output redirected to a file or piped to
another program (e.g., DSMADMC.EXE -consolemode >
/usr/tmp/adsmconsole.log).

On an AIX system, such output could be monitored via the "tail -f" command
and further piped into an awk or sed script to trap the messages you want.
 If the dsmadmc command is actually running on an appropriate machine, you
could probably pipe its output directly to the awk/sed script.  What you do
with the selected messages when you trap them is up to you.

At Haltek we actually market, commercially, our own MVS to AIX or NT file
transfer program (over SNA connections) which does support user exits
triggered on completion of the transfer.  I have never considered using it
in this way and am not sure whether you could apply it to this situation.
 Of course, if you have a full MVS TCP/IP suite with appropriate LAN
connections you can probably use SMTP routines on MVS to receive messages
and convert them into WTORs.

Good luck, and let us all know how you go.

Murray Nicholas
Systems Specialist
HALTEK PTY LTD