MIMO chirp tirgger problem using ADF4159 & ADF5901?


I'm using ADF4159 & ADF5901 to generate 24GHz radar chirp, and I have used the TXdata of ADF4159 to trigger a single sawtooth brust. I follow the INITIALIZATION SEQUENCE of ADF5901 to lock it at 24GHz and trigger the TXdata of ADF4159, and only one ADF5901 TX channel and LO channel work. I wonder how can I switch the TX channel of ADF5901 and cooperate with ADF4159 TXdata to get TDM-MIMO-FMCW signal? 

Thank you!