Last week, we had the author of TDD for a Shopping Website LiveProject. Friday at 11am Ranch time, Steven Solomon will be hosting a live TDD session just for us. See for the agenda and registration link
If you put a vector in request scope, it will be available to the JSP you're forwarding to, but it will not be available to the Action class that's called when the JSP's form is submitted. The reason for this is that request scope only lasts for the duration of a single request. Once the JSP has been rendered into HTML and sent back to the browser, anything placed in request scope is now out of scope. When the user presses the submit button, that starts a new request.
If you want to keep a vector or some implementation of java.util.map in your ActionForm and update the elements based on what the user enters, you may want to consider using "mapped properties" as explained in this link. Even here, though, you will have to implement some sort of "lazy initialization" in your ActionForm if it's in request scope, because the vector or map will have to be re-instantiated and re-populated each time a request is submitted.