Currently, there is no easy way to get a list of transactions for a given subscription id. To get a list of transactions for a subscription id. I load the subscription to get the customerProfileId and payentProfileId, call getTransactionListForCustomerRequest(customerProfileId, paymentProfileId), loop over the transactions returned in the response, and evaluate if transaction.subscription.id is equal to the subsciptionId I am looking for. Furthermore, getTransactionListForCustomerRequest() uses paging, so I may need to call that API multiple times to get the collection of transactions for a subscription.
I am requesting there be a new API to get a list of transactions for a subscription id. The new method would implement the standard paging and sorting.