Reg : additing Custom operators for search CRM

Hi all,

Actually for  date based search fields allow 'EQ',LT,GT,BT automatically.

But according to my requirement , I need to add Custom operators like below.

01--- Last 7 days

02---Last 14 days

03-- Next 30 days

I have added the operators in impl class method GET_DQUERY_DEFINITIONS. I can see the operators 01,02,03 values in drop down.

How I can add description and also where I need to add Calculation part like ... if user select 03 , input field should populate 09/02/2013 to 10/02./2013.

I have tried all methods in Context class , GET_RELATED_OPERATORS, ADJUST_TOCONTEXTUI etc... but no luck.

Regards

aj