There's a gal in our county who is excellent with behavior problems of cats and dogs (and other pets too). Here's a page of her website with various topics:
http://www.centerhillschool.com/behaviorissues.html
You can also email her from there with the info you posted on the forum and she'll reply. Be sure to put something in the subject line that will grab her attention since so much email is dumped into the junk mail folder these days.
Interesting it's always a hard surface — like there's a reluctance to do any digging at all. Maybe because of sensitive feet? Cats are very interesting. We love them. Report back to us all so you can be an encouragement to others when you get the GREAT SUCCESS you're hoping for!! :)