I'm not sure which type of growl you are looking for (just a tiny growl, a high scream, or a low death growl, etc), but I actually have a
document full of Japanese growl tutorials I've translated. There are at least 3 different methods on that document ranging from using things like Charsiesis, VocaScreamer, and other types of distortion.
Since my document is so long, I'll just write the simplest method that uses the Vocaloid editor alone (without using extra VSQ plug-ins). It just uses Pitch Bend and Pitch Bend Sensitivity in a saw-tooth shape.
Hamnare's method (follow link for audio):

They set Pitch Bend Sensitivity to 8 and used Pitch Bend to draw saw-tooth shapes. It kind of sounds like a rattle snake, though.
niu's method (follow link for audio):

They set Pitch Bend Sensitivity to 18 and drew the saw-tooth shapes much more irregularly (which I think sounds better).