Can you try:
ProxyPass /
http://localhost:8080/atriumkm/
?
It's the tomcat doing the redirect right now (use firebug, go to net,
activate persist, then show the headers: Apache-Coyote/1.1) so maybe
that helps things.
You might want to keep
ProxyPassReverse /
http://localhost:8080/atriumkm/
(this cares for redirects emitted by tomcat)
But I am still fearing you'll get some bad links
Paul