@Sampletekk you don't get a script reference to the convolution node directly - this would prevent the ability of compiling the scriptnode network later. You need to set the audio file slot in the convolution node to an external one (click the button next to the audio file in the node, then choose External audio file slot #0 or #1 or whatever).
Then you use getAudioSampleProcessor("ScriptFX") to fetch a reference to the scriptnode network and then call getAudioFile(0) to get a reference.
This translates 1:1 for when you compile the scriptnode to C++ and load it into a hardcoded FX module.