Well, if it says you can in the manual, it can't hurt anything by just being a 4 pin and not an 8. You'd be perfectly safe to try it.
The manual just says ATX power supply and doesen't specify an EPS as mandatory, so you should be fine. It'd be their fault for not complying with specs anyhow; that would mean that if the 4 pin caused probs, so would the 8 pin.