Recently I started implementing ARB on application (using php-sdk) and the implementation went smoothly until I hit a road block. I was not able to pull transactions for a subscription. In fact what, I would really prefer is to use the merchantCustomerId to pull all the transactions for that customer. Both, getting transactions for a subscription or getting transactions for merchantCustomerId, is all implemented on the merchant interface, but we are not able to use it through the API. So i know the integration between ARB and CIM is there, just not exposed to us developers.