QuickDriver TWAIN drivers?

I develop scanning applications that have to suport multiple scanners.

Can anyone explain to me the relationship between the ISIS and TWAIN drivers that come bundled with Canon scanners

and which both ISIS and TWAIN bear the ISIS logo and claim to have been built with EMC QuickDriver?

In particular, I am interested in which version of the TWAIN specification they support. Especially 1.91 which introduces MSG_RESETALL.

If the TWAIN driver is simply mislabeled as being created by an EMC product, I apologize for raising the issue here; but would appreciate that confirmation.

Many thanks,

Clive