No pytasz o to samo. Bo jak nie ma takiej opcji w ACP to nie ma odnośnie tworzenia użytkownika.
Jeszcze możesz spróbować z tym: https://invisioncommunity.com/developers/docs/members-authentication/login-methods/creating-a-usernamepassword-handler-r174/
/* Otherwise, we need to either create one or link it to an existing one */
try
{
/* If the user is setting this up in the User CP, they are already logged in. Ask them to reauthenticate to link those accounts */
if ( $login->type === \IPS\Login::LOGIN_UCP )
{
$exception = new \IPS\Login\Exception( 'generic_error', \IPS\Login\Exception::MERGE_SOCIAL_ACCOUNT );
$exception->handler = $this;
$exception->member = $login->reauthenticateAs;
throw $exception;
}
/* Try to create one. NOTE: Invision Community will automatically throw an exception which we catch below if $email matches an existing account, if registration is disabled, or if Spam Defense blocks the account creation */
$member = $this->createAccount( $name, $email );
Oczywiście to wycinek z tamtej strony. Trzeba się przyłożyć, by to zrobić. Możliwości są.