Maxwell Render

Hi

I'm trying to organise the shader tree in Modo so that illumination is provided by a physical sun and reflections from IBL.
I can't seem to get both at once. This is how my shader tree is looking:


The floating cube is chrome/mirror and the ground is a default material.

The environment containing the blue cloudy sky is set to 'Background' and 'Reflection'.

Why am I getting reflections from the IBL but no strong light from the physical sun? As soon as I turn the blue cloudy sky layer to invisible the strong light and shadows of the physical sun return.

I've tried different enviroment group orders and loads of other combinations of options but nothing seems to work.
In case it make a difference I'm using the 2.5110 Plugin with Modo 501 SP6 on windows 7. Any help really appreciated, this has been an issue for me for a while now.

Dave

I'm not sure if this is something to do with this but thought it worth mentioning that if I add a second Directional Light/Physical sun to the scene and then try and chose it for the Maxwell environment I get the error shown below:

So now it's working!
I don't know how I fixed it. I can't recreate the problem. I ticked and unticked options, deleted the enviroment material under the blue cloudy sky, put it back.. reloaded and it seems to work.

Does anyone else have trouble with this? I need to work out if I'm being thick or if there's more to it...
Here's the proof