Add spree_paymill to the Gemfile of your spree store
gem 'spree_paymill' , :git => 'git://github.com/webionate/spree_paymill.git'
Add stylesheets to your all.css manifest files *= require admin/spree_paymill *= require store/spree_paymill
You currently also need our version of the active_merchant gem, because it contains additional code for the paymill gateway
gem 'activemerchant', :git => 'git://github.com/webionate/active_merchant.git'
Don't forget to run Bundler
$ bundle install
Login to your backoffice of the spree store
Go to configuration >> paymentmethods and add a new payment method
Spree::BillingIntegration::PaymillCreditCard and submit the form
You are receiving 2 additional input fields to enter the private and public key from Paymill
Login to the Paymill backoffice, copy the keys from there, enter them in the Spree backoffice and submit the form again
You're ready to go!
spree_paymill is currently in a testing phase. It is already capable of handling payments and refunds via credit cards (MasterCard and Visa). Handling of debit cards currently isn't supported. Although we've tested spree_paymill on our systems, we currently don't guarantee, that it will work in your environment too.
If you want to use spree_paymill in a production environment you'll have to contact Paymill to receive live keys.
Just contact us via our website