[ic] Authorize.net & fallback to GPG?

[Grant]

I currently save payment data with GPG and process it manually via an
Authorize.net "virtual terminal" written in ITL.  I'd like to set up a
system so that when an order is placed the payment data is sent to
Authorize.net but the card isn't charged.  Then I can issue a command
to Authorize.net later to charge the card.  I'd like the payment data
to be saved to GPG as a fallback if Authorize.net can't be reached.

Has anyone implemented anything like this?

- Grant