unfortunately I think this is not possible. Have you contacted your cisco office ? Perhaps they can check with engineering if there is a way they can provide a command to enable B-channel loopback in order to pass B-channel loopback test.
However, the whole controller can be put in loopback and this is enough for an accurate BER test.
Introduction: The "external-out enable" command is available for
configuration under the "router ospf process" in case of the IOS-XR
operating system. This command basically enables advertisement of
intra-area routes on the device as external routes in th...
Introduction Basic configuration for netflow Scale parameters for
netflow Netflow support Architecture Packet flow for netflow Inside the
LC CPU Netflow Cache size, maintenance and memory Sample usage Cache
Size Aging Permanent cache Characteristics Which...