I am reading that cast iron may pop or crackle in a convection oven, and aluminum is best for it. Since Le Creuset Dutch Oven is just enameled cast iron, I couldn't help but have a safety concern over using it in the microwave's convection mode.
Le Creuset and convection ovens work well together.
One issue may be that some microwave ovens turn on the microwave part even in convection mode. More honest ones call this combination mode, and have a separate convection mode (like mine).
There are a couple of potential issues even with decent convection microwaves. One is that it will take a long time to heat through in a fairly weak oven. Another is that it's likely to be quite tricky to get a full size one in.
If you're using it with the lid on (if it even fits), the lid will come very close to the element. That's where the biggest issue arises, because the (oven-proof plastic) knob on the lid can't take that much direct heat. In some models the (top) element is far enough back that it won't directly heat the knob. In others I wouldn't trust it not to damage the plastic.
I don't have a pot of that specific brand, but I've several enamelled cast iron and steel pots and they work fine in my microwave combi oven when used in (convection) oven mode.
Of course you have to make sure that you have the correct mode selected before turning on the oven (do NOT use the combined oven/microwave mode for example), but you should do that regardless of what you put in it.
I've been doing this for over 15 years, never had a problem and the pots nor the oven are any the worse for wear as a result.
Main problem you may have is finding one that's small enough to fit in the oven, as they tend to be rather small compared to dedicated convection