AU preset directories / importing AU presets

Hi there,
I am having trouble with Ardour pulling up presets for AU plugins (McDSP Revolver & Analog Channel, and Abbey Road 12413 compressor specifically). I can insert the plugins but cant get the factory presets to pull up. Can I import them? What is the file path for plugin presets? I have the ilok plugged in and like I say the plugin inserts just fine but cant get the presets up which is especially needed for the Revolver reverb! I would appreciate any help!

I am running Mixbus fyi and can save and retrieve presets just not pull up the factory presets…