Yeah, doSubmit needs to receive the request name. For example
So, once you submit, the easiest way to accomplish this is to set the values via the Branch. Use the URL Target as you described, but use the branch to do that.
Hope this helps.
You can't use doSubmit to pass variables; it will only submit your page with the request you passed in. All normal page processing and branching will be followed.. Why are you using doSubmit? Just put the URL in the URL field.