Get ComboBox ValueText from Value

Hi, i have a ComboBox with this parameters:

Value     Text

A            AAAA

B            BBBB

C            CCCC

D            DDDD

I need a method that returns "AAAA" to input "A" .

I have found two similar method "getDisplayItem" and "getSaveItem", but they use numbers to identify position of item (Es 0,1,2 etc...).

Otherwise the method "boundItem" the input "AAAA" returns me "A". I  must use the opposite.

Anyone can help me?

Kind Rergard