Adding quantity from invoice lines to project lines view/explorer screen.

We are starting to you use Project accounting, and find the explorer window great. However, the quantity invoiced in the vdvproject lines view, seems to be inaccurate. Infact, we would like to quantity from invoices lines view. I have tried a couple joins, and attempting to look through the schema, but cant seem to find the link between the mods. They must link somehow, because if i enter an invoice, i can add project and project number into the invoice.

Any help is much appreciated.