Converting PWM audio to xmega DAC audio... ??

Hi and seasons greetings from London. :) I am currently working on a synthesis project and am using the engine of a brilliant 2 op FM synthesis sketch by GordonJCP from github. It uses DDS methods and PWM DAC implementation for the audio. The amazing piece of code is here: https://github.com/gordonjcp/gyoza/blob/master/fmtoy/fmtoy.pde

I was just wondering if anyone could give me any help with porting the audio part so I can send it out of a a DAC in a different way... I have an Xaduino board which is an XMEGA 128 chip with its own modified Arduino IDE (1.0.1) which can also be used like the original IDE. There is a library for the DAC which is basically the same as the XMEGAduino DAC library. I would like to have a go at changing Gordon's code so it can be sent through the DAC but I'm not sure how I would go about it... The PWM uses timer overflow vector interrupts and the Output compare register for the actual audio output and uses a sine tables of the operators. The audio is updated in the loop(). Please, is there anyone out there that can point me in the right direction?? Thanks. Steve.