bonnex, go and download Helios. When that's done, do the following:
1. Go to Helios and click Profile > Add Interface
2. Add DCS A10C and your TM Warthog throttle
3. On the bottom-center of the Helios window, where it says Bindings, click the Output tab
4. On the Actions window, open your Interfaces > Keyboard and on the Bindings window, select the button you want (verify with the image on the top-center of the Helios window), in my example I used Button 2 which is Mic Switch In
5. Drag the "send keys" from the Actions window onto the button you want (in my case, button 2)
6. On the Value box under the Properties window, enter the PTT button you have set your VAC profile on, in my example it is Right ALT so I put in RALT
Here is a picture of step #6 for clarification:
Each time the Button 2 is pressed, Helios will make it seem like you just pressed your VAC PTT button.
Hope that helps!