Searching for the XML tags won't get you anywhere, because those get generated from data, they're not hard coded into the procedure. Instead, look for procedures that are generating XML from resultsets.
Search sys.sql_modules for '%FOR XML%'
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability