Hi Lynne, thanks for the advice, I was also thinking the same, my problem is that I cannot find the template or file where I should do this changes
--------------- Added [DATE]1219849291[/DATE] at [TIME]1219849291[/TIME] ---------------
UPDATE: I find it

the template I need to change is this one:
rssfeed_body_template
--------------- Added [DATE]1219849856[/DATE] at [TIME]1219849856[/TIME] ---------------
UPDATE: I find something else, on the same RSS Feed Manager, when I edit the Feed, It shows the option to change the way it's posted.
Thank you very much Lynne