Just like you would any other situation where you need bare wires. Cut off the plug, and strip the wires, both skills you will need anyway to run the signal wiring.
Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum
The PS-14 does not have two wires without ends. Instead it has an adapter. How does Digitrax expect you to connect a power supply that is not configured.