Smiting Power( Champions of Valor, p. 33)
You use your smite ability to augment other combat maneuvers.
Power Attack (PH) , ability to smite,
You can use your smite ability (whether smite evil or from some other source) when making a bull rush or overrun attempt. If your smite ability would normally grant a bonus on your attack roll against the target of your bull rush or overrun, you can add this bonus to your Strength check instead. In addition, if you win the opposed check to bull rush or overrun the target, you deal damage to the target equal to the bonus the smite would grant on a damage roll against that creature. You must announce the smite attempt before starting the bull rush or overrun. If your smite attempt would not grant a bonus against the target of your bull rush or overrun attempt (for instance, if you used smite evil when bull rushing a non-evil creature), the attempt is wasted to no effect.