This should be included with Overloader, however if otherwise, copy the DLL files and this HTML file into C:\<Buzz Path>\WaveOutput\. And change the output driver in Buzz's Preferences to "Overloader Output Extender".
OOE (Overloader Output Extender) is one of the core parts of the whole new 1.5 overloader system. It allows overloader and its extensions to see the samples that are outputted after the Master Machine.