Just back from holidays and what a suprise!
I would like to know about the DSD support and where I can find more about it. 
Anything in HELP files?
Cheers

it allows you to import and export DSD files but internally converts the data to PCM for processing along with any other audio. It doesn't actually process in DSD.

There is some info around, have a look around the website.

DSD support seems to work just as you might expect: You can load an export DSD files, in either of the common formats (DSF and DFF). Sonar looks like it supports all the common DSD sample rates too.
 
Other than that I image they work like any other audio file. Sonar almost certainly converts them to PCM because you are going to need to operate on everything in the same space and everything it does is PCM. That aside, there are extremely few audio processors that can handle DSD audio (it is mathematically difficult to do).
 
It isn't really that useful of a feature, unless you are mastering SACDs, but hey.

Much appreciated fellas,
I have looked but not found details.
But you guys have pretty well answered what I most needed to know.
Export as one of the DSD fille types and sample rates. 
What this means is the ultimate in upsampling of your mix to a more linear format for mastering via an analogue chain
 
I have Korg"s Audiogate which is free to download and plays the DSD file types. 
 
Tascam also have a quality DSD recorder. umm
I don't know if you have heard recordings made on DSD , notably acoustic material has much more detail.
There are plenty who argue against this, obviously they haven't used one.
There a quite a few who swear the sound of a mix on their prized mixboards is upheld with DSD.
Unfortunately only crude editing is available and and creative editing requires conversion back to PCM kind of defeating the purpose. 
It is not for all, but I am really interested where Sonar might go with this.

Some more information in this thread.

Cheers thanks