a) Please don't reopen year old threads. Especially ones with only a tenuious connection to your question.
Thanks..I'll never open old threads
b) You don't set it in the FileOutput node; it's an ES ...
Where to set this property in FileOutNode.
set OutputLocalEnvironment.File.Name =
InputLocalEnvironment.File.Name || cast(CURRENT_TIMESTAMP AS CHAR FORMAT 'YYYYMMdd_HHmmss');