Interestingly, while you are running the game and connected to Studio via Live Link, you can actually upload new impulses into a Convolution Reverb and you can hear the change in real time. Live Link only updates user data not audio assets - but the Convolution Reverb impulse is actually user data. The XML file becomes huuuuuuuge if it contains a Convolution Reverb with a long impulse.
However, there is a way…