If I choose any output on the Output Device drop down it works, but iShowU and Soundflower will not. It just simply plays through the default output, even if Soundflower/iShowu is set as the default output in the OSX system settings. Soundflower and iShowU work fine in Sibelius and Logic X.
OSX High Sierra 10.13.6
FMOD Studio 2.00.11