Edit: After some reading, it looks like this BGC can come with or without IMU. I was assuming it had an IMU and that you only wanted to point a camera that was already being leveled. Maybe you want to actually send it the leveling signal? That might be doable too (but I suspect not). We support PWM outputs to gimbals (that normally go to servos), but those outputs must be connected to something that acts like servos connected to a gimbal. So the question becomes whether sending this controller a fixed PWM signal causes the gimbal to hold a fixed position (constant position with position controlled by PWM signal width, that would work as it is like a servo) or whether a fixed PWM signal causes the gimbal to hold a fixed speed (constant speed with speed controlled by PWM signal width, would not work with LP gimbal signal). I suspect that it would hold a fixed speed. That would require some sort of IMU to be mounted on the movable part of the gimbal and would not work with LP gimbal signals.
You mean use it with LP? (or something else like change it's settings using LP)
Most (?) gimbal controllers have standard PWM inputs to allow you to move the camera (e.g. when in a stationary hover). This is usually just taking a channel straight from the RC receiver, or if the receiver uses a single signal wire protocol like SBus, there is a way of using e.g. an unused servo/ESC output (PWM) for one of the receiver channels pass through.
Vehicle page you just set one of the Accessories (0,1,2,3) to be one of the input channels. Then on Output page you configure it how you need. Be aware that some outputs must share the signal rate, so you probably want to move things around so that the gimbal, probably running PWM@50Hz, is not on the same bank as an ESC which you want to be faster than that.