Content Access / ACL with Invoicing

I could not find a similar issue, so just taking a stab at this...

I was thinking that since there is not really a Customer Interface at this time, invoices could be made with viewing and access could be given to the Customers to view only via ACL, however, after setting root permissions, then assigning individual invoices to their customers, a customer can still see ALL invoices.

i think this would be a great workaround for this module and would expect its download/useage count increase substantially.

or possibly I am missing a step...

Thx
Norgo