Connecting alternate power source to shield

I'm new to using the arduino and purchased a motor shield to help me with a project. I have the seeed motorshield 2.2 hooked into the Arduino, and a 6V external power supply hooked into the shield. The shield is working correctly, and does power the motor like it should, but it doesn't appear to be using the external power! The motor is unphased if I turn the external power off while it's running, and it drains the 9V that powers the Ardrino VERY quickly. I have the EM_BN jumper cap on, and the motor works if I connect it directly to the external power supply with relays which I was using first.

How do I get the seeed motor shield to power my motor with an external supply? No one else seems to be having this problem as far as I could tell looking around at other tutorials.

Information on the shield itself can be found here:

Thanks for any help! Tim

Power Jack: Provide power to drive motor when the jumper MB_EN inserted.

I assume the jumper is inserted??