Project Site Reporting

In Report Builder 3, I am trying to report on some lists in Project Sites.

I can get this working using some guidelines using an XML data source, however I want to use the "Microsoft SharePoint List" option instead. It looks a lot more easy to build reports this way, just select the required fields...

With this "Microsoft SharePoint List" option, I have to specify the project site URL, but this is no good as it obvisouly then only returns site data for that project. I need it to indentify what site url belongs to the selected project.

Can anybody help?

Thanks