[cflsystems]

If it is not working you are doing something wrong or in the wrong place. You need to follow the stock code and find where customer gets redirected. At login if customer already has cart the redirection is to the cart page otherwise to the page from which login was called. If it is new customer and this is "register" the redirection is to the account page.

Check the handleRequest() method as this is going to be where the request is being redirected to one place or another then just follow the code. Your parameter is not stripped form the url it is just that the redirects are hardcoded to specific page and existing url params are not passed on to the redirected url.