Back to my first email message when I thought you were already using OpenNMS... You have to uncomment the Linkd service in etc/service-configuration.xml, then restart opennms and give it some time to probe. Then it should show from the 'View Node Link Detailed Info' at the top left of a node page. The weakest part of the program is the web admin section. While it does a lot, there is much more that you can control via the xml config files.
Thanks again, Les, this is going to be a very useful tool for us!