Your UFT manual has an area that talks about GEDCOM and how it works in UFT and some of the options. You might start there. If you do not have the manual, look under the Help section of your program. There is an on-line manual included with the program.
I'm still working on the Reunion and Gedcom capability with my friend. She's been quite busy; but I promise to get back to you as soon as I find anything out. You might want to go to the Reunion site at http://www.leisterpro.com/http://www.leisterpro.com/ and see what they say about Gedcom, too.