Hi,
I was wondering whether it is possible to link a PWM signal to a MAVLink command throught the pixhawk cube using a Lua script?
If so, where should i start?
I have general knowledge of Lua scripts, and have used them for simple servo control ect. (Thanks to Yuri’s ArduPilot Lua Demos)
You cannot yet send or receive MAVlink messages via Lua.
Yet! - Sounds promising 
It’s been a topic of discussion more than once. The consensus is generally to provide a backend binding to whatever method acts on the MAVLink message of choice rather than internally routing telemetry messages.
It’s typically not difficult to add a script binding, and the dev team is usually receptive to pull requests for such.