Originally Posted by
J.C. Koto
Unless I'm completely misunderstanding, it sounds like you're doing it wrong. The part the wires are inserted into is a removable plug/connector. You should only have to insert the wires once then you can remove and reinstall the plug with the wires attached. I suggest you take another look at the manual to see how it works.
I agree with J.C. Take a look at this Shimano connector which yours is said to be based upon:
Shimano Dynamo Hub Connector - Longleaf Bicycles
Walk through the pictures to see how you fix the wires into the connector, then the connector just plugs into your hub.