<?php

abstract class Ebanx_Gateway_Model_Payment_CreditCard extends Ebanx_Gateway_Model_Payment
{
	protected $_canSaveCc     			= false;

	public function __construct()
	{
		parent::__construct();

		$this->ebanx   = Mage::getSingleton('ebanx/api')->ebanxCreditCard();
	}

	public function setupData()
	{
		parent::setupData();

		$this->data->setGatewayFields(Mage::app()->getRequest()->getPost('payment'));
		$this->data->setInstalmentTerms(
			$this->gateway->getPaymentTermsForCountryAndValue(
				$this->helper->transformCountryCodeToName($this->data->getBillingAddress()->getCountry()),
				$this->data->getAmountTotal()
			)
		);
	}

	public function transformPaymentData()
	{
		$this->paymentData = $this->adapter->transformCard($this->data);
	}
}

<?php

abstract class Ebanx_Gateway_Model_Payment_CreditCard extends Ebanx_Gateway_Model_Payment
{
	protected $_canSaveCc     			= false;

	public function __construct()
	{
		parent::__construct();

		$this->ebanx   = Mage::getSingleton('ebanx/api')->ebanxCreditCard();
	}

	public function setupData()
	{
		parent::setupData();

		$this->data->setGatewayFields(Mage::app()->getRequest()->getPost('payment'));
		$this->data->setInstalmentTerms(
			$this->gateway->getPaymentTermsForCountryAndValue(
				$this->helper->transformCountryCodeToName($this->data->getBillingAddress()->getCountry()),
				$this->data->getAmountTotal()
			)
		);
	}

	public function transformPaymentData()
	{
		$this->paymentData = $this->adapter->transformCard($this->data);
	}

	public function persistPayment()
    {
        parent::persistPayment();

        $gatewayFields = $this->data->getGatewayFields();
        $this->payment->setInstalments($gatewayFields['instalments']);
    }
}

Add instalment on quote process
Add instalment on quote process
