W210 webasto z/c possible to retrofit digital controller

Hi

Hope someone can help..I have searched the Internet to no avail!!

I have a working webasto thermo top z heater booster in my e320 Cdi, which assists with heating of coolant on cold days.

Is it possible to retrofit a digital clock control, or even just a simple switch to the heater in order to pre heat the water and interior prior to starting the engine. I appreciate this is possible for other models of thermo top, but cannot find information on thermo top z fitted eom to Mercedes?

Thanks in advance

Ada