I (Harry Fearnley) cannot find out what "itaji" means. However, I can find the word "ateji" that seems to have a meaning similar to what seems to be meant here. Please see the Wikipedia page on "ateji" at http://en.wikipedia.org/wiki/Ateji
What about this - http://www.sljfaq.org/afaq/itaiji.html
On the page it is actually itaiji, not itaji