Website Optimizer for affiliates

I found the webinar on split testing very useful and I'm looking forward to using Website Optimizer to split test one of my new sites, but I'm wondering how affiliates use this tool since we don't have access to a conversion page.

I know you can use script to have a link go to another page on your website and then redirect the user from there and use that as your conversion page, but in my case, I have a form in my website and the user fills out the form and the data is submitted to the merchant site, so that method might not work for me.

I was hoping Google would let you define an action as a conversion and then you could just define a button click as a conversion.

James