Its a lot easier that one may think. 
 

 
I know that a few of us love this plugin. To get it to work in Sonar is simple. Download DXshell. Here http://www.kvraudio.com/forum/viewtopic.php?t=177538 Its a free utility for converting DX plugins to VST. Sonar wont load 32 bit DX plugins but it will load 32 bit VSTs. Work on this it easy to place the DX dll for FX3 in a folder under VST and place the DXshell dll there with it. When Sonar scans it will see a VST for FX3. 
 
If you have questions ask them here. BTW I was expecting a lot of trouble but I ran into none. 

Cool John! A blast from the past:)

Its blast because no other reverb has the same sound. I wish that CW would update it to 64 bits without loosing its unique qualities. Until then we can use this "workaround" to have it in our toolbox. 
 
BTW its free though it may need a serial no.. I had bought it a long time ago and have one.  

John
I wish that CW would update it to 64 bits without loosing its unique qualities.

Now there's some Platinum bonus FX content worth having!
 
EDIT: not meaning to imply at all that the rest isn't:)

Nice, John I remember using it back in the day Would definetively be cool if Cakewalk did a 64 bit of this.
All the best.

Thank you, genius. This one of those progs where you go "what happens if" ..... I move that wall etc. Great fun.

I grabbed all the FX (1,2 and 3) when they were offered by CW for free.
 
The FX3 version I have shows as v1.0.  Interestingly, there is a 1.01 patch (with some fixes) in the knowledge base:
 
https://www.cakewalk.com/Support/Knowledge-Base/2007013159/Audio-FX-Patches-and-Updates
 

I have to say I do really like this plugin. If it were not what it is and as cool as it is and as fun as it is I wouldn't bother. 
 
I'm glad so many of you have found this thread useful. 

One of the best plugins ever. I had hoped it would get multi-channel inputs - instead it was laid to rest

Bring it  back cakewalk.