Over 19 in under 19?

They say that you are only as old as you feel. But does ICC believe in that way of determining age? One Ben James Write from England made a century against Pakistan in an under 19 test match on 5th of August 2007. He was 243 days over 19 years on that date. He was not the only one in his team over 19 years. One Adam Lyth of the same England under 19 side was 314 days over 19 years of age on that date and he also made a century against Pakistan on the same date.

Now, I wont accuse England of anything yet as I am not very sure of what the rules say. When I discovered it for the first time (thanks to muradnyc of banglacricket.com), what I did was some research on the topic. Another keen member on the same thread provided a link to the rules on determining age for the under 19 world cup. I am quoting a line from the rules here: "To compete in the ICC U19 CWC Players from Full Member countries must be under the age of 19 on the 1st of September before the event takes place and Players from Associate or Affiliate Member countries must be under the age of 20 on the 1st of September before the event takes place."
But amazingly, I cant find any rules for other under 19 tournament. At least the ICC website does not talk of any rules for determining age for an under 19 test series. If someone can throw some light, please help clear the confusion.

Reference:
Ben Writes' profile on cricinfo
Adam Lyth's profile on cricinfo
Spinners put England in control
Age Determination Policy for ICC Under 19 Cricket World Cup

Thread by Muradnyc on banglacricket