Where can I modify Datatypes default behavior?

Hi. I wanted to change the default behavior of the Document (File Name) datatype so that it will include the full UNC path along with the file name when a file is selected. The default behavior is to just save the file name, but I need to store the full path since the location where a file was found is important to the application that I’m working on.

Is there a way to edit the code that controls different datatypes so that I can save the full path rather than just the file name?