Использование пользовательского поля из карточки сотрудника в БП

$documentService = $this->workflow->getService('DocumentService');
$document = $documentService->getDocument($this->getDocumentId());

$userId = CBPHelper::ExtractUsers($document['CREATED_BY'], $this->getDocumentId(), true);


$filter = ['ID' => $userId];
$params['SELECT'] = ['UF_поле'];

$listResult = CUser::GetList('id', 'asc', $filter, $params);

if ($row = $listResult->fetch())
{
    if (is_numeric($row['UF_поле']) && $row['UF_поле'] > 0)
    {
        $this->SetVariable('MyVar', 'user_' . $row['UF_поле']);
    }
}

$userId = CBPHelper::ExtractUsers($document['CREATED_BY'], $this->getDocumentId(), true);

$USER_ID = {=Variable:Ruk};

$USER_ID = $this->GetVariable('Ruk');