thanks for bringing this to our attention, we will look into what updates need to be made and get an update for eCart out to fix this.
in the mean time, one thing you may try is to edit the VPSProtocol element to change the version on the confirm page:
<input id="VPSProtocol" name="VPSProtocol" type="hidden" value="<?php echo("2.23"); ?>">
change that to:
<input id="VPSProtocol" name="VPSProtocol" type="hidden" value="<?php echo("3.00"); ?>">
probably won't be the only change that needs to be made, but it's worth a try.