It is pretty much done.
There is a sample here. viewtopic.php?f=24&t=422
That was a preliminary version.
It has changed since that.
Download info has been added that required some changes and invoice printing will also have some changes.
This will show the basic concept. You can also check the demo. Guest account is there.
New additions for version 1.2.5
Re: New additions for version 1.2.5
It' ready. Checkout from SVN.