The following link should provide you with the information you're looking for:
Hope this helps!
Thank you for the link but I´m looking for.
I understand HTML but very little XML.
I get the flags "in"; now I saw them as a shape option but I couldn’t associate a code in order to create the relationship flag name and country name. I suppose that it may be quite easy, since the flag name and the country code have the same name (and different extension); I am looking a way to do this. I know from the link you sent me that the relationship is established via the preferences.tvs file...I´ll keep trying.
Thanks, once again!
Your country field will need to be placed on the shelf, and then you'll have to assign the correct flag to the appropriate country within the shape legend.
Hope this makes sense!