Your stepper motor could possibly drive your feed belt but it's very difficult to say without knowing the torque and speed required. A better choice would be a DC gearhead motor (they are more efficient and easier to drive than a stepper). Robot Marketplace has a good selection of gearmotors http://www.robotmarketplace.com/products/motors_main.html although you could probably find a used motor for less on Ebay.
I would strongly suggest that you determine the torque and speed requirements before you select a motor. The manual for the machine in the video gives a spec of 150 W for the motor with a belt feed speed of 0-6 m/min.
If you use this information with the diameter of the feed belt roller you will be able to calculate the RPM's required and choose a motor based on this and the wattage of the motor.
As to the equivalence of your stepper to a PMDC motor, you would have to look at the torque curve chart for the motor in question as steppers develop the most torque at low rpm's and PMDC motors at high speeds.