Jim,
The pre-woven cane you speak of is fairly easy to replace. There is a special chisel to remove the old spline if it still in the groove. First, make sure that the inside lip of the groove is rounded a little along its top edge. This will prevent the groove from cutting the cane as the spline is hammered in. Next take the cane and cut oversize (around 1" to 1 1/2" all the way around). Fill a pan or your tub with warm water and soak the cane for 4 to 6 hours. It should be very soft. While the cane is soaking, prepare 4 hardwood wedges that will fit into the groove, pointy end down and blunt the pointy end a little. Once the cane is ready, place it over the seat, align it properly and drive one wedge into the top groove, middleways. The wedge should bind itself in there. If not, the wedge's end may have to be cut a little more. Stretch the cane toward the bottom edge and wedge it likewise. Do the same to the left side and then the right. Then starting at the top pull the wedge out ( the cane should stay mashed into the groove) and gradually work your way around the seat with a wedge mashing the cane in as you go. Remove the wedges as you get to them. Now run a bead of yellow glue in the groove and follow with the spline. You will need to really smack that spline down into the groove and I have always used a rubber mallet for this. I generally follow the smack-down with a wedge and really set the spline as deep as possible. The seat will be pretty tight at this point, but when it dries it will tighten up like a drum. Now just take a razor knife a trim the excess.

I would recommend a company by the name of H.H. Perkins for you cane needs. They sell prewoven (1/2" is the most popular and strongest) and the spline for the groove width (they vary) as well. Their website is listed below.

: I'm restoring a canoe for a friend. Can anybody tell me how to replace cane
: seats? These are the type that are made from pre-woven material which is
: pressed into a routed dado with a spline. The frames are ok but the cane
: and splines are shot. I can buy the cane off a roll at a local woodworkers
: shop but didn't see spline material and have no idea how to assemble it.
: Thanks