I just upgraded to Sonar 4, and needed VSC for my files too. I had
Sonar 2 on an older computer. Here's how I installed it.
-copy the "Program FilesCakewalkShared DxiRoland" folder from old Sonar installation to same location on Sonar 4 machine.
-run notepad (Start | Run... then enter: notepad) and enter this exactly (4 lines, without line break in the HKEY line):
[HKEY_LOCAL_MACHINESOFTWAREClassesMfxSoftSynths{429C9236-361F-4E6F-AA9A-FF39E614EF5D}]
"Description"="EDIROL VSC"
"HelpFilePath"=""
"HelpFileTopic"=""
-save the file as "vsc.reg"
-from command-line (Start | Run... then enter: cmd):
cd "Program FilesCakewalkShared DxiRoland"
regsvr32 Rvi01Dx.dll
regedit vsc.reg (click Yes)
-start Sonar, and VSC shold be installed.
Since these steps modify the registry, use at your own risk.