RL78/G13 - 16 bit data transfer over SPI

Hi,

I am using RL78/G13 microcontroller. I need to communicate with AFE031 (powerline data transfer chip) over SPI . In AFE031 registers have read and write operations are need to transfer 16 bit data. But our controller have a 8 bit data transfer at a time .

I was tried to split data in two no of 8 bit data to send in buffer. But I can't get the expect output from the registers. I received as 255 at all time. I can't get output. 

Is that problem occurred due to the 8 bit data transfer over SPI or that is not necessary?

Is it possible to transfer 16 bit data over SPI ?

Please help to find that problem.

Thanks,