The USB-6008 is too limited to let you timestamp incoming trigger signals and its AI sample rate is pretty low as well.
The USB-6210 should be capable of both. Sorry, I'm strictly a LabVIEW guy and can't offer any specific C++ help. To fully sync the two tasks, you'll probably need to look into configuring an "Arm Start" trigger for the counter task that timestamps the trigger signals. The same signal would be used as a regular Start trigger for the AI task.