Can you use the RPM activated switch RAS on a 7AL3 (the new black one) to activated a CO2 shifter?

yes

Any instructions or diagrams.

The CO2 shifter solenoid does not draw many amps so if you wanted to do it simply just run a hot wire 12v to one side of the solenoid and hook the other side (ground) to the RAS terminal.
Your solenoid doesn’t mater which wire you hook to positive or ground.
The RAS supplies a ground not hot.
You can also use a relay but not necessary

Also make sure you hook a jumper wire from your ignition positive to the RAS on terminal.

Here is using a relay and what B.J. Is referring to