Try to concentrate on closing the ankle joint (dorsiflexion) while in heelside carves. Pull the toes toward your shins. This will help direct more force to that turning edge and really drive it into the snow. Also, have you tried adding some forward lean to your highbacks? It will make your heelside more responsive and easier to lock into carves. Aggressive forward lean will also force you to get a lot lower to keep your heel edge from engaging on jib features, so watch out for that. Start small (again) and bend those knees!