You can allow a reseller to set up and use his or her own merchant account or operate through the provider merchant account. Make sure, that the list of associations between the processing centers and payment systems is configured in the System > Settings > Payments Processing > Payment Methods. Mark associations as default to be copied to a reseller. The reseller can configure default associations or add his or her own ones.
Note: If the reseller's sales currency differs from the provider's one, the reseller may use only his or her own merchant account to accumulate funds.