There are settings for the lock power for different solvents in the probe file (located in ~/vnmrsys/probes/<probename>). Also see ~/vnmrsys/maclib: there are macros to change/add such parameters to the probefile, "addlkpars" and "setlkpars". Moreover, there is a macro called "setlk" that contain solvent information and powers... Of note, you might need to uncommented lines in this latter macro to activate them.

I have never changed any of these settings (nor use automation) so I can't give you more detailed information, but I think the solution will be somewhere there. I hope this helps to put you on the right track...