I do a fair amount of surf fishing, and this is a common issue for our Korkers. I had to find a link. This will give you some ideas to work off of:
http://www.stripersonline.com/t/392712/modified-korker-photosalso:
http://www.stripersonline.com/a/korker-modificationThe soles off an old set of shoes, rubber radiator hose, some stainless steel nuts, bolts, washers, and some shoe laces, and your all set.
Here's what you need to do 1 pair of adult korkers.
70 pieces of each (buy 100 at Jamestown Dist for big discount
http://www.jamestowndistributors.com/ )
-Size 10-24 3/4' long SS machine screws. Pan head, philips drive
-Size 10-24 Nylon lock nuts
-Size 10 flat washers
For the straps you need 5/8" radiator/heater hose. You can find it at Sears Hardware, auto parts store, probably Home depot, etc.
As Im sitting here thinking about it, if you dont have old boots to cut up, trace the outline of the boot on a thick piece of rubber mat and cut it out for the sole. Chances are she'll out grow it before she wears it out.
See the link for directions and pictures
Hope it helps
Kb