openldap meta to active directory bind err=49 most explicit return information ?

Hi,

I have a meta that proxify bind requests to 3 AD.

A CAS server use the meta backend to authenticate users.

if I connect into the cas ui with a user and good password , all is fine. if I connect into the cas ui with the same user and a bad password , it's fail , all is fine if I connect into the cas ui with a another user (password expired on the AD) using the good expired password,  it's fail , all is fine

But I want to have a information windows that says : "bad password " or "password expired" , I cannot because return code is always  ' RESULT tag=97 err=49 text=   '

Did someone knows a way to get the information ?  ( same question with "locked account" and all the existing case )

Regards

Nicolas