rx-7: Congrats on the radio...
sorry, but the 3D doesn't have the SRO feature, you can adjust the rate via a button on the handle or you could set up auto dual rate with very high steering at very low speed(I wouldn't set-up the auto dual rate this way).
If you want to see more features of the 3D, you can download the manual at:
Hitec or
Lynx 3D PDF Manual