Paymill extension for Magento (Version 1.5.x - 1.7.x)
To install via Magento Connect login into your shop backend and go to System > Magento Connect > Magento Connect Manager and upload the PaymillPayment-1.0.1.tgz extension file from this repository. Afterwards go to System > Configuration > Payment Methods and configure the Paymill payment method (insert your Paymill test or live keys).
To customize the Payment form you may edit the file /app/design/frontend/base/default/template/paymill/form/paymill.html after installing the extension.