variable active protection system

[gevaudan]

Does anyone know of a way in which to automatically enable active protection system when on batteries alone but disable it when a DC source is plugged in? I have a thinkpad t42 and searched through both the powersetting and the active protection system tool(s) but did not see what I am looking for.

Has anyone else tried to do this successfully? I would not think there would be many 3rd party tools available that could provide such a high level of customization for such specific hardware but who knows. Any suggestions are appreciated.