Few CE manufacturers are willing to give out the technical information describing their IR codes and signalling protocol. We engineers usually end up reverse-engineering it (luckily it's rarely that hard). Beats me why they think it's worth 'protecting'...

I'm disappointed by Kenwood creating the situation in which you find yourself, to be honest. That shows a certain lack of respect for their customers, in my opinion. Remote power on/off is hardly an extra feature worthy of charging for...

The easiest way around it is to visit the store where you bought your DVD player, and see if they have the remote, and will let you learn that one code. Once you have it, you could use ProntoEdit to make it available here for others (if you were feeling generous :-)