Adapting Rainsoft Gold valve to tank with Q2

I am in the processing of swapping my old Q2 head with a Rainsoft Gold series that I received. I noticed that the way these two valves attach to the down tube are different. What would i need to adapt this? The Q2 used an adapter that screwed into the bottom and had o-rings that fit down inside the down tube, but the Gold uses something that is press fit with an o-ring in the valve bottom instead of it being threaded like the Q2 was. There was also a small about 1/4" diameter tube with the Q2 that I can not figure out where it goes on the Gold valve. Any help would be appreciated. I can get pics if needed.