The Bank Transfer Funds Transaction is not yet available for scripting and web services. We do have an existing Enhancement Request logged for this feature request.
Here are the enhancement details:
Enhancement 170963 Web Services / SuiteScript >Transactions > Bank > Transfer Funds > Expose Bank Transfer Transactions.
Also when you check the SuiteScript Supported Records (SuiteAnswers ID: 10242) the record type for fund/bank transfer is not listed.