Are you pressing both triggers at the same time? Because if so, that won't work.
What our team did to test the xbox controllers was something along the lines of this code:
Code:
for (int i = 1; i <= 6; i ++)
{
System.out.println("AXIS "+i +" READS "+joystick.getRawAxis(i);
}
If you run this in your teleop code, and monitor the NetConsole, you should see Axis 3 read a value of near 0when neither trigger is pressed, a value of near 1 when one trigger is pressed, and a value of near -1 when the other is pressed.
If you can confirm that Axis3 does behave in that manner, then joelg236's code should work with the addition of setting another solenoid when the value is > 0.7.