If you use the Data Assist wizard to create the pages, WA DOES handle it..
theres more than one way to skin a cat. By doing the pages manually rather than using the wizard, there are certain things that wont get created for you.
Form builder wont create the action of the form to pass the query string, you would need to add that ability.
Like i say theres more than way to do this. In your page, you where using the recordset binding for the ID column value. another way to do it would be to store the URL variable that is passed in to a hidden element, and use the hidden element as the ID column value.