S1 Corp.'s Postilion unit said Tuesday that eService SA, the acquiring unit of Poland's PKO Bank Polski SA, plans to use more components of the Postilion merchant acquiring offering.

The acquirer, which already used Postilion's platform, has agreed to add back-office processing components to handle settlement, management reporting, and chargebacks, the Norcross, Ga., vendor said.

"We required a transaction management platform that would provide the settlement services and reporting information that our business needed," Maciej Maciejewski, eService's technology and research department director, said in an S1 press release.

In addition, eService will use Lean Industries Inc.'s AdjustmentHub, which is integrated with Postilion's products, to handle aspects of chargeback requests and re-presentment processing.

S1's Postilion unit targets mainly smaller financial companies, while S1's Enterprise unit markets banking technology applications to larger financial companies.