How to retain Date value in ajaxcontrol extender on Postback

Question

Dear Friends,
i am using some date controls like start Date & End Date in my Web Form with Ajax Calendar extender,
but somehow on DropDown Postback event the value inside the Date controls gets lost and  i have to re-enter the value again which is not good as per User.
and dont want user to edit the date controls only select the particular Date...so it should be read Only(non-Editable).


Pl reply,

Regards,
Aamir