XY Homing Offsets

Hi There,
The XY endstops on my i3 type printer is 10 to 12mm outside the printing area. It is fine for X and Y homing but not for the Z Probe which does not sense the buildplate. Is it possible, for example, to move the X axis immediately back 10mm from the endstop after it homed and say that position is X0? The same is true for Y.
I use an Arduino 2560 board with a Ramps1.4 shield and Marlin 010107 firmware.
Thank you

Just enable (uncomment) "save z homing" in config.h. Than printer will move sensor to center of bed (in you have entered correct probe offsets).

Thank you, I will give it a go

You should also set
// Travel limits (mm) after homing, corresponding to endstop positions.
#define X_MIN_POS -10 ;<<adjust as ness
#define Y_MIN_POS -10 ;<<adjust as ness

so that 0,0 is the front left corner of the bed