Dear Jack,
Please find attached a .zip file which I took from a Knowledge base article entitled "Cable Mapping for a 68 Pin Connector to a 50 Pin Connector" in here you will find a the pin-outs for a 68 pin connector and a 50 pin connector for the E-series boards. When you use the SCXI-1302 you are essentially converting the 68pins of the PCI-MIO-16E-4 to 50 pins, so follow the 50 pin connector diagram and you will see which connections you need to make.
Regards, Sally Tipper -NI.