[galaxy-dev] Output external file stored outside galaxy-dist dir

Hi all, I'm Venice and I'm new in Galaxy. I installed a local Galaxy and I just want to know how I can output to history an external file stored outside my galaxy-dist folder. I created an xml explicitly stating the absolute path, but when I run the tool, it says "Either this dataset does not exist or you do not have permission to access it." I don't know what to do so I do hope you can help me with this. Thanks and Best Regards, Venice Juanillas