I'd suggest another book to read called Parenting with Love and Logic:Teaching Children Responsibility. Basically the book is based on the premise that every choice has a consequence. Some are good, some are bad and teaching them to live with the consequence of the choice they chose. Kids talk back or disrespect because they thrive on parents giving the kids emotion and kids thrive on emotion. It might be worth looking into. I know my kids school has had lectures from the authors and uses it daily as do we at home and we've seen our kids really turn around in their problem areas.
Hope you get it figured out!
Heidi