There is only 2 ways to "add" a ponytail.
Look for a superstar that has long, untied hair. Make parts of the hair transparent, shaping it to look like a ponytail. And then re-texture it. Mr. Perfect has such hair.
The other possibility is to add it to his back textures. It will be completely flat.
Go into 80las thread. He made a long-haired Giant and Earthquake based on Big Show. That may give you an idea on how a pony-tailed Paul Wight may look.