by going to WebAssist -> Security Assist -> Authenticate user, you are inserting a new instance of the User Login server behavior, not editing the one that was created by the security assist wizard.
to edit the server behaviors created by the wizard, you need to open the server behaviors panel, open the page it is applied to, and double click it to edit.
to change the registration redirect:
open the registration page, open the server behaviors panel (Window -> Server Behaviors) in the list of server behaviors on the registration page, double click the Insert record behavior and check the redirect.
to change the success login redirect:
open the login behavior, open the server behaviors panel (Window -> Server Behaviors) in the list of server behaviors on the login page double click the Security Assist Authenticate user server behavior, and check the login access redirect.
NOTE: on the login page, there may be 2 instances of the authenticate user behavior, one is used for the login form, the other is used if the auto login checkbox is checked, make sure to edit both.