Do you have any other kind of device you can use to test? A dock doesn't do much if there's no other hardware to plugged into it. If you have a thunderbolt hard drive to plug into it, that would be a better test. Most of the time Thunderbolt is not able to be hotpluged, so when you plug into it, you have to reboot with the device on. I know you know this and already tried doing so with your interface, but do you have another device to try with it?
I let the UAD apollo at work it's the only peripheral with thunderbolt i've got BUT ... i've changed a parameter in the bios of the blade in the thunderbolt tab
i've put no security instead of user control (or something like that i don't remember the exact name)
maybe it change something for the hotplug you maybe can try this
and maybe it could have make my thunderbolt work it's strange because
when i plug the dock in the thunderbolt port in the system infos it says "pas de gestionnaire" in french "no manager ?" see the picture
when i unplug the dock it says no hardware found that's okay
for you to know i've installed osx on an external SSD that i've plugged in the dock and i was able to boot and to use the ethernet port on the dock but maybe all of these are controled with the usb controller
i'll try again my apollo monday i let you know if i find something or if it works
thanks for your help