Hi Vishnu,
1. Since yours is opportunity search scenario, the relevant view would be:
BT111S_OPPT/Search
The view implementation class is : CL_BT111S_O_SEARCH_IMPL
Here you should see the method "GET_DQUERY_DEFINITIONS". Inside this method, depending on the search criteria, the V-HELP would be defined.
In the same class, you can see the event handlers EH_ONVHELP*. You can put a breakpoint here depending on whichever attribute you want.
2. For the role field, is a V-Getter already defined? if so, in the V-getter method definition you will need to add:
APPEND INITIAL LINE to <<lt_ddlb>>
Where <lt_ddlb> is the table with drop down values.
Hope this helps.
Regards
Nisha