When you are configuring the DA search on the second page you just need to get the values that are being posted from the first page rite? If so you are on the right track and have the pages setup correctly. In order to get the form bindings from your first page available on the second page you will need to open the second page, go to the bindings tab and add the binding for form data. When the dialog opens select the first page. This will put the bindings from that form on your second page in the bindings panel. Now when you configure the DataAssist Search server behavior and you need to reference the select list from the first page you just click on the lightning bolt icon and select the value.
This form data binding option is very helpful and an easy way to access data that is being posted from another page. I think you have got it mostly worked out correctly, please give this a try and let me know if there are any other issues.