Sabenaboy,
If the new code was given to you by Belgrade ACC or Zageb ACC (over the adriatic sea), it was done not for the identification purpose, but due ORCAM (European code allocation scheme) requirement. It means that you are identified with the code you are transmitting, however, we have to give you a new squawk in accordance to set of codes assigned to EUR region D.
The book says it all and this was just an attempt to give you one more (operational) reason why squawk ident is not needed.