I was describing my method for winding a back-to-front warp on the AVL Warping Wheel to someone on WeaveTech, and he asked me to post photos next time I did it. So here are the photos:

(I apologize for the rather busy background; my studio is in the garage, and this was the best I could do.)
Basically, what I do is remove the “comb” from the top of the wheel and attach another cross-maker in its place, to hold the raddle cross. This is clamped onto the wooden comb-holder – see the stuff inside the red box on the left side of the photo.
The threading cross is located inside the red oval to the right of the photo. This is the standard AVL cross-maker, which I purchased from AVL. However, the standard cross-maker will not work for constructing the raddle cross – the dowels are too long and it would be difficult to attach – so I made my own and clamped it to the comb.
Here’s a larger photo of the raddle cross-maker holding the raddle cross:

You’ll notice that the threading cross is below the warp as it’s wound onto the warping wheel, while the raddle cross is located above the warp. This is necessary since the warp needs to be unwound from the outside of the wheel. If the raddle cross were located under the warp as well, it would be impossible to unwind the warp without losing the raddle cross. (I found this out the hard way!)
The one problem with winding a back-to-front warp on the AVL Warping Wheel is the lack of end loops. I solved this by separating the back of the warp into several sections, tying knots at the end of each section, and adjusting the tension on each section until they came out even. This was a bit time-consuming, but not particularly hard.
I hope this helps!
Hi Tien, I don’t understand the photos of your “raddle cross maker”. I have been interested in doing this for some time and like what you are saying but don’t totally understand it.
Marta