CH and
Saitek rudder peddles both need to have the brake axis inverted/reversed in the DCS options axis control panel. I also recommend setting up curves and Y saturation to help soften the initial input of the brakes.
Left/Right brake:
Y Saturation = 85
Curve = -20
Slider selected
Invert selected
Would also recommend a curve of like 20-30 (depending on personal feel) for rudder control. Make sure rudder assist and take off assistance are off, you want to learn how to use those rudder peddles properly as soon as possible.
When taking off, RPM at full and you only need 35-40 MP to take off (if not loaded with weapons) and no flaps. This will help you control the torque.
Tail wheel - Stick full back to lock the tail wheel to the rudder, full forward to unlock.
Covered quite a bit here, try these things out and let me know if it helps.
/Salute