[Boost-users] Building Boost for Comeau

In the explanation for como-win32 toolset configuration variables, the variable COMO_BACKEND_PATH, which says "Path to backend compiler" has a default value of $(VC7_TOOLS). Running vcvars32.bat for vc7 does not set any such environment variable. To what does the COMO_BACKEND_PATH need to be set ? Is it the path to the backend compiler executable itself or is it the path to the entire installation ? If I had Vc7 installed in c:\vsnet, would COMO_BACKEND_PATH be c:\vsnet or would it be c:\vsnet\vc7\bin ?