Getting 2001 Smartcraft into calibration mode

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Hi! I just bought a 2001 Mercury Optimax 150 with "smartcraft" (They actually dont say smartcraft, but look just the same)

I am unable to get these into cal1 or cal2 mode! I have tried holding the two normal buttons. And also any other combination I can think of.

Picture of the back of the gauge is here:

http://yfrog.com/mwbildej

Thanks