I found a 20 pin connector at Mouser. Just go to www.mouser.com
The connector is part number 538-511102050. The sockets that go into the connector are PN 538-50394-8100. Be sure to order some extras as I messed up a couple when I was attaching the wire.
I just soldered the wire to the sockets. They are crimp on but I don't have a crimper. You'll need to snip off the strain relief part of the socket so they will fit into the connector.
Just be sure when you wire it up you note the pin numbers are from the component side but the connector is on the bottom of the board so all the pin numbers are backassward. If you email me at firstname.lastname@example.org
I can send you a drawing I made up of the connector from the bottom of the board that makes it a lot easier to keep the pin numbers straight.