Hi,
1)Please use a flag variable in your internal table as a field.
2) for example:flag type boolean."char1.
3) and go to table control property in screen painter and give the work area name .
4) For example: wa_table-flag .
following links will help you with code:
http://scn.sap.com/thread/455443
http://scn.sap.com/thread/1759645
thanks,
vidyasagar