Stretching exposed roots on a Negari style Chinese Elm

I have a Chinese Elm with a coiled exposed roots system. I would like to stretch these roots out and over the side of the pot to begin a semi-cascade tree. Is there anyone that has a method for stretching the roots. I have some ideas but thought that someone may have a tried and true method. The look I am going for is like the picture below:

OK so I found that it was very easy to do. I anchored the pot using lath across the top to hold the bottom of the roots (the buried roots). I was able to tether the upper trunk using tubing to protect the bark. Because it is in an oversize plastic training pot, I made a hole in the rim, stretched and leaned the exposed roots over the side and secured with wire. It doesn't look pretty, but I think it will set quickly and then I can start pulling the foliage down into place. After it sets I will post some pics. I think it will work well.
Tona