You can interactively import and export DFA files from the following NX menu options:
File→Import Assembly into Teamcenter
File→Export Assembly outside Teamcenter
See the NX Manager Help for details.
DFA files can be imported/exported along with the mix-ins (or mix-in tree) automatically. More than one dfa file can be selected one after another and can be imported/exported together.
Parts can be exported along with DFAs that were instanced in the part. You can do this using Add DFA with part in the interactive dialog box.