OK, I've been playing around with HitFilm 3 Pro for a several months and noticed a few things. Wanted to make sure before saying anything.
One, is that when I add an Ambient Light to a scene it does nothing to light it. At full intensity the scene is dark through the active camera. Even if I duplicate it (creating two Ambient Lights in the scene) it's still dark. Yes, "Visible" is checked under the light's Layer Properties and "Illuminated" is checked on the model's Materials tab.
In other 3D programs I use the Ambient Light is represented in the scene and is able to be moved around using the XYZ handles (even though that doesn't do anything). In HitFilm, there is nothing representing the ambient light in the scene - it disappears like it's not there. Changing it to another light type brings it back into the scene.
Asus Laptop - N61Jq
Windows 7 Home Premium - Service Pack 1 64 bit
i7 CPU Q740 @ 1,73GHz
AMD Mobility Radeon HD 5730 with 1GB
8 GB System Memory