public function actionNeco()
{
    if($this->user->inRole('admin')) {
        $this['addUserForm']->setDefautValues(...);
    }
}

public function renderNeco()
{
    if($this->user->inRole('admin')) {
        $this->template->form = $this['addUserForm'];
    }
}

// ...

{if $user->inRole('admin')}{control addUserForm}{/if}