src/ShopPaymentIPNBundle/pkgShopPaymentTransaction/objects/TPkgShopPaymentIPN_TransactionDetails.class.php
public function getAdditionalData($key)
    {
        if (true === isset($this->additionalData[$key])) {
            return $this->additionalData[$key];
        }

        return null;
    }
public function getAdditionalData($key)
    {
        if (true === isset($this->additionalData[$key])) {
            return $this->additionalData[$key];
        }

        return null;
    }
public function getAdditionalData ( $ key ) { if ( true === isset ( $ this -> additionalData [ $ key ] ) ) { return $ this -> additionalData [ $ key ] ; } return null ; }
here you can get additional data like the transaction id from the transaction details,
If key not exists return null.

@param $key

@return mixed|null
here you can get additional data like the transaction id from the transaction details If key not exists return null .