Hi Raj,
When you said
you did this
Enhanced default view
Added required fields to view to appear in the view
written code in DO_CONFIG_DETERMINATION method to change button descriptions.
Did you add a new context node to the context after enhancing the view?
or you just added the fields from existing context node to the custom view configuration ?
Because for second option you don't need to enhance the context node.
In any case calling of custom DO_CONFIG_DETERMINATION is because you enhanced the view. So this should not be the cause for not calling DO_CONFIG_DETERMINATION.
Regards
Vinod