That power cord should work fine, Ive been using one for a printer in my xbox for a while, I lost the original one.
Also, just something funny, when I got my first xbox (like a week after launch), it didn't come with a power cord! They just forgot it or something.
Then the dvd drive broke, it was replaced under warranty (with another 1.0), then the dvd drive broke again (it was a phillips this time), but it was like a week after the warranty went out. So I took it apart and fixed the drive, but then the HDD died. I tried to mod it to replace the drive, but just screwed it up. So i got a new xbox (a 1.4), modded it, and its been great ever since!