Well the way the agreement was set up, the shares apparently transferred direct to the ANZ on the back to back AMSLA, so Opes Prime was not really considered a pricipal borrower and had no rights through the transfer of title, they were agents for ANZ, Merril and Dresdner really if you look at the immediate transfer of title from the rightful beneficial owners who were the Opes Prime clients.
Opes Prime would be considered an agent due to the pooling and the immediate passing of title to the priciple borrower. This is the case in the UK and the USA.
This arrangment should have been clearly disclosed in the transaction.