[amsat-bb] gpredict and ft-817 cat control

Does anyone know a way around the problem that gpredict can only control the FT-817 downlink frequency. I suspect there is a limitation in the hamlib control for this rig. The gpredict manual says 'the TX frequency can not be adjusted via the CAT interface (e.g. Yaesu FT-817)' but SatPC32 on windows manages to handle TX and RX so it must be possible. Dick G4BBH