Hi ,
You should be able to do this using an event and a programmer sound.
You then register a callback in the Event API for a programmer sound, and pass it an FMOD::Sound pointer that has been opened with System::createStream using the shoutcast/icecast URL.
You can get the Lowlevel FMOD::System::createStream API (fmod.hpp) access via the Studio API’s FMOD::Studio::System::getLowLevelSystem (fmod_studio.hpp) function.