this is mycode of combobox,

<rich:comboBox id="send" value="#{canalsData.sender}" suggestionValues="#{canalsData.sendersnew}" 
                                                                                                               directInputSuggestions="false" defaultLabel="Select Designation"  width="125" enableManualInput="false">
                                            
                                </rich:comboBox>

sender is String varaible and sendersnew is ArrayList,
i have added values to arraylist like this sendersnew.add(id,value) ...
when i change the value in combobox i want to get id into backing bean,value is displayed in combobox..how to do this..i am unable to do
please any one can help me............