If you don’t see any of the Arnold render channels (like Arnold_Alpha or Arnold_Opacity), open up the script editor (press ALT+4) and run the SITOA_CreateRenderChannels() command.
Tip – You can avoid this by making Arnold the default scene renderer. The SITOA plugin will then make sure the Arnold render channels exist (by calling SITO_CreateRenderChannels from OnNewScene and OnStartup events).
hat tip to Francois Lord for pointing this out
# Python Application.SITOA_CreateRenderChannels()
// JScript SITOA_CreateRenderChannels();
eX-SI 
Also, setting the default renderer to Arnold in your preferences will create them when you do a New Scene.
Thanks, I forgot about that.
Does softimage shaderballs work with arnold?
No, the shaderballs don’t work. Arnold doesn’t support multi-universes 🙂 The scene is one universe, and a shaderball would be a second.
shaderball
“Hardware Renderer” renderer default
Preview of texture and color is possible.
thankyou! very useful for me!