How to use remote to control video with Canon SX1 IS?

I just got a Canon SX1 IS digital camera, which came with a wireless
controller. According to Canon support, it's capable of controlling
video. Here's part of Canon's email response:

"The remote is pretty straight forward. You can zoom, play, pause, and
stop the recording using the remote but the camera will need to be set
to the video mode."

So, I start the video recording, turn the display so it's facing me, then
sit in front of the camera, but none of the buttons on the remote do
anything. I double checked that the batteries are installed correctly.
The documentation is very vague. Can anyone tell me what I'm doing wrong?

-Thanks