T903 6 Pad calibration

How to calibrate a 6 pad system. This is done in pairs so calibrate pad 1-2, 3-4 and 5-6 together. If only 1 of the pair is calibrated the not calibrated pad might giver UUUUUU error. Mode setting in the F1 menu dictates if this is a 2, 4 or 6 pad system.