Reading & Displaying the current signal on an external signal head

[gehringerg]

I have a USB connected signal head that I would like to use to display the current signal indication.
I have the signal working with MSTS and it added to the simulation experience.
Looking at the Raildriver.dll API, there does not seem to be a function to return the state of the signal, however the LUA scripting interface seems to provide that information.

Is there a hidden API call to retrieve the signal state, just like the lat/long ?
Using the LUA scripting route, would I have to add code to each and every scenario to return the signal state or would I have to modify each and every engine script - I just don't know...

Any hints or pointers would truly be appreciated and the knowledge learned would be return to the forum.

THANKS in advance for you help
--Gary