Dynamic Parent Child drop down List in Dynamic accordion control - Child drop down losing SelectedIndex

I am generating Dynamic Accordion Panes which contain 2 Dynamic Drop Downlists. One is dependent on another. Parent Drop Downlist has AutpoPostback, and it works fine. The selected value is retained properly on postback. On parent drop down selection change I am again calling the same Load method on postback to populate child drop downlist , then adding code to selectedindex event method to repopulate chidl dropdown list based on the value selected in parent Drop Down. Child drop down does not have AutpoPostBack. I also have dynamic buttons inside each accordion pane. When clicked on the button, FindControl finds both the drop down lists, but shows correct index only for parent drop down. How can I retain selected value for child drop down too?