while downloading to excel from internal table how to wrap the text of excel column

Dear Experts,

         I am trying to download internal table data(lt_tab) to excel using the below code

wdr_task=>client_window->client->attach_file_to_response(

                                         i_filename  = 'RTM Report.xls'

                                         i_content   =  xtext

                                         i_mime_type = 'EXCEL' ).

Note: In the above xtext is xstring which we got after the concatenation of internal table data and then passed these string to FUNCTION MODULE "SCMS_STRING_XSTRING".

         Here the problem is my itab is having one string field so how to wrap this cell content,any one could you please help this is greatly appreaciated

Thank&Regards

kranthi