What Webbot is eluding to is there is Software-based PWM, and Hardware-based PWM.
In hardware PWM, it's a 'set and forget' type of thing. In this sense it is better, but there are only a small number of hardware PWM pins (as you have realized).
In software PWM, the software pulses a pin really fast - just like code to turn a LED on and off. The disadvantage is that this takes up some processing power, but you can use any pin to do this.
This is why the Axon II has 2x as many hardware pins.
The WebbotLib Project Designer lets you use one or the other, or both at the same time, and is really easy to set up.