Change next button behaviour

[Mr Wolf]

Hi to all!
Ok, I tried to search on Google, but I couldn't find any solution.

I'd like to change the default behaviour of the "next button": instead of opening the next item in a playlist, I'd like it to go to the next chapter, for example, while playing a DVD (instead of starting it from the beginning).

By the way, I tried to add the "dvd menu" button to my toolbar, but it's never showed, neither when playing a DVD.

Thanks in advance for your help.