I would guess that the pressure of the CO2 cartridge would push the valve in for you...the spring pressure inside the valve is only a couple pounds (since you can push it in with your finger), and the PSI of the cartridge is (don't quote me) prolly 100+psi. No valve actuator needed.
PRODUCT INSTRUCTIONS:
http://www.stopngo.com/products/inflation/1090.pdf
1. Slowly thread the CO2 Canister onto the larger (bottom) brass fitting.
2. Thread smaller brass end of valve adapter onto the tire valve all the way.
3. Use pliers to firmly grip adapter where it meets the Canister.
4. Grip Canister firmly on protective foam tape (Avoid skin contact to metal).
5. The final twist of the canister will puncture the seal and allow the CO2 gas to escape into the tire.
6. Your tire valve prevents new inflation from escaping during this process.
7. After the desired air pressure is achieved, remove the valve adapter. Replace with regular air pressure as soon as possible. Used Canister is made of recyclable material.