My Dog Won't Go!?!?!
Use a trail that smells and looks like a trail to your dogs.
Now, lets look at your end of it. Skijoring is a team sport. Dogs and people working together. Your dog will provide momentum, but, as my friend Lorne likes to say to his skijor student's "It's not your dog's job to haul you around the trail!". So put in some time on your skis, and be a team member your dog can brag about! Your dog will pull better if this is a team sport.
Still won't go?
You have a few options here.