public function EntryController_RegisterValidation_Handler($Sender) {
      // Require new fields
      $ProfileFields = $this->GetProfileFields();
      foreach ($ProfileFields as $Name => $Field) {
         // Check both so you can't break register form by requiring omitted field
         if (GetValue('Required', $Field) && GetValue('OnRegister', $Field))
            $Sender->UserModel->Validation->ApplyRule($Name, 'Required', $Field['Label']." is required.");
      }
   }