Turns out that it has (so far) nothing to do with ssh tunneling, and was
all about giving us access (they specifically mentioned via PuTTY) to a
"non-IBM" server that one of our Tomcat contexts will be running on, so
we can upgrade it to Tomcat 7 (and presumably either preserve or
reinstall our context).
Though I don't think I'm going to rule out ssh tunneling in the future,
on this installation.
What I know about ssh, and 25 cents, might buy you a cup of coffee. What
I know about PuTTY and 75 cents, might buy you that same cup of coffee.