Webservice : Retrieve customer payments for a customer across all A/R accounts

Hi,
   Please share any ideas on fetching the customer payments for a customer across all A/R accounts?
Currently the code below will fetch records from default A/R account only:

InitializeRecord initRecord = new InitializeRecord();

InitializeRef reference = new InitializeRef();
reference.setInternalId("997");
reference.setType(InitializeRefType.customer);

initRecord.setReference(reference);
initRecord.setType(InitializeType.customerPayment);

InitializeAuxRef iar = new InitializeAuxRef();
iar.setType(InitializeAuxRefType.arAccount);
initRecord.setAuxReference(iar);

ReadResponse result = null;
result = this.netSuitePort.initialize(initRecord);

This logic needs to extended to fetch customerPayment of the given customer from all A/R accounts.

Thanks,
Harley