Avamar cannot browse Sharepoint farms after installation

Working with a customer on a "simple" Sharepoint configuration (single front-end server with a database server) - we have installed the Avamar agent and the MOSS plugin on both systems, and we can see those "components" when browsing from the Avamar Admin GUI.

And of course, when we click on the "Sharepoint VSS" component, it asks us for credentials - but when the customer provides the Sharepoint administration credentials (which are set to log on as a service), a "Farm" level shows below the Sharepoint component, but no farms display and we get a "10007" error.

The documentation talks about the Sharepoint account requiring "domain level administrator rights" - the customer found that requirement "bizarre". He also mentioned that Sharepoint had been installed with one account, but that the current administration account was a different one.

Also, the documentation mentions an "Avamar Plug-in for SharePoint VSS agent service" when talking about the account privileges - where does this show up in the Services listing and what is its name?

And speaking of services, from what I can tell, all of the required Sharepoint services and writers that are needed are present and running.

What are we missing here? All comments/feedback appreciated - thanks.