It would be nice if we could inherit the forms of the security module and extend its functionality or design, but there is some hard code to call directly those forms. i.e. the function “check_password” calls the form “svy_sec_main_user_password_tbl”, so inheritance can´t be done properly.
One possible solution is use the configuration properties to define a prefix or a naming convention for forms of the framework, so won´t be a direct call to them, instead you should ask if there is a form matching with the defined convention. An idea could be have a global function in the framework to return the correct form to use based on the property