Saving a sheet in excel work book as txt file.

I am trying to save a specific sheet, for example sheet#3 of an Excel worksheet to a tab delimited txt file in PowerBuild 12.0 using OLE Object. 

The code I used: myoleobject.ActiveWorkbook.SaveAs(lsFileNameTxt, -4158)  saved a different sheet than #3.

When I tried other methods such as myoleobject.ActiveSheet.SaveAs(lsFileNameTxt, -4158), or myoleobject.Application.WorkBooks(1).WorkSheets(liIdx_DataSheet).SaveAs(lsFileNameTxt, -4158), I got errors.

Please help...

Thanks, Ping