Auto XML generator with custom information

Hello! I need a Wordpress Script that generate custom XML with properties details. I'm using this template: [login to view URL] Remember: This kind of template use Custom Fields, so I need that this script allow me to choose which fields I want show on the XML. But... this script needs to allow me to change the tags from XML, like: Normal tag is: Bathroom Customized tag (I will choose): Bath Because I want to post my properties in ads websites like OLX and so on. By the way, if possible it should be automatic (cron) and let me generate multiples XML files for multiple sites (So I don't need to configure each XML-generator everytime).