Modify my Ultracart checkout so it sends intermediate data

I have a project with the ultracart shopping cart API.

I have a shopping cart with upsells. This cart should be transmitting updates to ultracart at every new page in the pathway, so that ultracart knows what items have been bought and then added. But instead, it only sends data at the end. This causes the following problems:

1) My first item is set to do a pre-authorization to ensure the card details are correct (this way the checkout can display card billing errors right away) Since ultracart doesn’t know the item was added until the end, the pre-authorization does not happen.

2) If the user closes his browser window on an upsell page, the entire order is lost, since ultracart never even sees the initial order.

See this video for clarification:
http://www.filedropper.com/111909checkoutmodificationdetailsc

Here is the javascript manual:
http://www.filedropper.com/javascriptcheckoutapi

The project is simple:

1) Ensure that ultracart gets the information at every step, instead of at the end, in order to fix the pre-authorization and “upsell page close” problems.

2) Make sure the checkout page cleanly shows the error codes

That’s it. This job should be quick for programmers knowledgeable in javascript.