What's up bud!?

I know which dog your talking about, maybe have the man try this:

Work the dog with the flirt pole outside, I know your dogs know the hide, and work a flirt.

THEN, take him inside, and slowly work on getting him to work a flirt/springpole inside. Once the dogs comfortable "working" inside, start setting him up on the mill, and try to use that same hide he's used to as bait.

Get the dog comfortable with "working" inside, then try to introduce the new equipment, but keep the familiarity of the hide.