Batboard

I have my Systems Saber III setup to properly transmit unit ID on PTT at the beginning of the transmission. I'd like to have to do it at the end of the transmission. When I go into RSS and change the MDC setting to after instead of before, the option for PTT ID disappears from the personality. Setting MDC back to before, allows the PTT ID option to show up in the personalities.

Is the SSIII just not capable of transmitting the PTT ID at the end of the transmission, or is there another setting I'm missing?