I have done this twice.
'Management >> High Availability' 'Configuration' tab
Completed basic 'Configuration' with no problem using Eth3, a name of "Node1" and 'Device Node ID' 1. I hit apply, and received the (grammatically incorrect) response, "HA settings has been successfully changed".
In 'Advanced', I selected "Internal" as the 'Backup interface' then checked 'Enable automatic configuration of new devices'.
When I clicked on the arrow to get the drop-down box for 'Preempt Node', the box was empty and IE blew up.
ASG220v1 512MB - Vista Pro SP1 - IE 7.0.6001.18000
Cheers - Bob