http://www.cakewalk.com/Support/Knowledge-Base/2007013099/Adding-third-party-audio-editing-software-to-SONARs-Tools-menu
 
This is all I can find but I'm sure there must be something newer??  
If not has anybody got this working in Windows 8.1? 
 
I had it working back with 8.5 and with Wave Lab under Windows 7 64 bit.. But I never got it to work since. 
I just bought a Sony USB Turntable and it came with a handy version of Sound Forge 9. 
 
 
 
 

I think someone made a util for this since Platinum.
It is in the user created utils but I could not locate it.
 

Here it is. by scook.... should have known .
 
http://forum.cakewalk.com/FindPost/3237117

Thanks a heap,,, it worked like a hot damn too. I forgot I had even downloaded the utility a long time ago. 
 

check out my signature. Follow it to SonarToolsEditor by scook.

microapp
I think someone made a util for this since Platinum.
It is in the user created utils but I could not locate it.
 

Its there. Called SonarToolsEditor

Thanks. I followed the instructions on the Cakewalk site and it showed up in the drop down menu so I thought all was well. Went to use it with a client in the room and NG. Will try scooks.

Michael,
This tells me that the syntax of the exec string is not correct.
The first time I tried this manually (way back)  I found that the syntax of the exec string was really picky.
Something about spaces or quotes I don't remember exactly.
Try scook's util and you should be good to go.
 

The most common error when directly editing the registry I have seen on the forum is adding a space between Wave and Editor in the type field instead of entering the type as WaveEditor. A bad path would cause a program not to launch. Another problem which occasionally shows up is a permissions mismatch. If SONAR is run as administrator, the external editor should be too. If SONAR is not run with elevated privileges, the editor should not either.

BTW, the KB article is still accurate. The tool I wrote helps capture the data but the end result is the same. I added a few extras not mentioned in the KB article based on a post Noel made a while back. I reference both the KB and Noel's psot in the tool help file.