Is there a program available that will disable the back light when the Treo's phone rings? How about disabling it only during (user defined) daylight hours?

I conducted tests with BackLight Hack, GlowHack, Keep-It-Lit Hack, Backlight Combo and AppLight Hack. All work as advertised in the usual sense, they do not suppress the back light from coming on when a call comes in. This is apparently a feature built into the OS, and so I'm looking for an app that might specifically address this necessity.