Setting pause position  

Setting pause position

I would like to set the pause position on an XL to the front of the printer. This would allow access to the print head when a tip cleaning is needed in the middle of a print. I have tried modifying the printer start-up code to add an M601, M125 or M25 command. For example: M601 X100 Y0 Z20 S. I believe this should set the pause position to X 100, Y0 and a Z lift of 20. The S at the end of the command is supposed to set the pause position rather than executing a pause.

But the command M601 X100 Y0 Z20 S results in an immediate pause and the pause position is not changed from the default.
An M125 X100 Y0 Z20 S command does not execute an immediate pause, but the pause position is not changed.
An M25 X100 Y0 Z20 S command acts like M601, an immediate pause is executed and the position is not changed from the default.

What am I doing wrong and how can I change the pause postion?