Yes this is a common problem in OO design. A standard solution is to use one of Factory Patterns, which are special structures responible for creating and setting up a new instantance.
I recommend you looking at the resorces explaining usage of FactoryMethod design pattern:
http://en.wikipedia.org/wiki/Factory_method_pattern - general theoretical definintion of the patter good to get a grasp of the concept
http://www.adobe.com/devnet/actionscript/articles/ora_as3_design_patterns.html - example within the flex context
http://flexscript.wordpress.com/2008/09/26/simple-factory-design-pattern/ - another simple example concerning the flex sdk
Good luck !
Excellent answer, thank you so much.
Good to hear that it helped You
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I had looked for the 'correct answer button' but it wasn't displaying in Chrome. Displayed the page in Firefox and it was there.