"mounting" helma app behind apache

Hi all,

I hope this is not an RTFM....
What I'd like to do is to "mount" multiple helma applications somewhere
in the PATH of my domain:

<VirtualHost foo.test.home:80>
  ServerName foo.test.home
  ...

  <Location />
     ProxyPass http://localhost:8080/ #thats jetty's http listener
  </Location>

this *seems* to work OK though I'm not entirely sure 'cause I was unable
to access the "manage" app. However:

  <Location /helma>
     ProxyPass http://localhost:8080/
  </Location>

lets me access helma from http://foo.test.home/helma but css breaks and
links don't work... I tried to set in apps.properties:

manage.mountpoint = /helma/manage
...
welcome.mountpoint = /helma

which results in:
HTTP ERROR: 404 %2F%2F+Not+Found
RequestURI=//
Powered by Jetty://


Question is basically how to make this work. I'm not bound to mod_proxy
in any way so any method is fine. I just feel I'm still missing the big
picture how this is supposed to work. Any advice, pointers to
docs/howtos are much appreciated.

thanks
 Paul