Hi Khalid,
The best place to go would be MicroChip forum.

http://forum.microchip.com/

Here, our compiler don't support them 'till now

Depending how accurate/fast you want your PWM signal. You could still roll your own using an Timer interrupt, or look for a bigger DsPIC with more PWM channel.... the biggest i know have 8 PWM channels in though

Why you need them in-synch?