ajax Tab With Update Panel

Question

i am using Ajax <pre lang="C++">TabContainer</pre>
there is a drop down  in tab the Tab Its bound with database (sqlserver)
and on selectIndex change Event Fired to fill the other drop down
(Post Back)...
I m using update panel to get rid of post back but its not working as it normally works ..
And I have some Controlls out side the <pre lang="C++">TabContainer</pre>
 as Well
So plz help me to let me know how should i Manage It??