I did this this summer by using a long .010 ( I think, it was thin) wire with a 90 degree bend at each end , resembling a 3 inch u bend. First I made a hole in the covering just behind the fin and another directly below in the bottom of the fuse through which the wire was threaded.
Next I made a groove in the front of the rudder at the bottom and attached one end of the wire with epoxy and glass cloth. The other end I attached to a Sullivan large tail wheel assembly. This took the place of the spring wire in the sullivan tail wheel. Also, I epoxied a 3/16 piece of plywood to the bottom of the fuse to mount the tail wheel assembly. It is not that comlpicated and works great. But, as mentioned above, you need to pre plan what you are going to do.
Sam