Normand,
What you said actually makes sense now. I think it wasn't until the 4th or 5th generation iPod that Apple finally standarized their "dock" connector. So a 5th generation iPod charger would charge a 3rd generation iPod touch (and vice versa), but a 3rd generation charger has a different pin out than the newer dock connector used in new iPods, iPhones, iPod Touch, and iPad.
Brian
"My father was very sure about certain matters pertaining to the universe. To him, all good things - trout as well as eternal salvation - come by grace and grace comes by art and art does not come easy." Norman Maclean, A River Runs Through It