<?$APPLICATION->IncludeComponent(
"bitrix:system.auth.form",
"demo",
Array(
"FORGOT_PASSWORD_URL" => "/login/?forgot_password=yes",
"PROFILE_URL" => "/login/user.php",
"REGISTER_URL" =>"/login/?register=yes",
"SHOW_ERRORS" => "N"
)
);?>
"REGISTER_URL" =>"/login/?register=yes",
?register=yes подключит system.auth.registration (регистрация),.