Is it possible to relocate C:\NetBackup Temp?

Even if the Windows client (any version) is installed on a different drive, a hidden directory called "C:\NetBackup Temp" is created and (based on the last modified dates) used for most backup sessions.

Is it possible to relocate this directory to another drive?  I've looked in the registry and the environment variables and can't see where that path/directory name is set.

I'm asking because on a few of our older physical systems C: doesn't have that much room left and on at least one occation I've crashed a box by filling up C: during a backup by what's written into that directory.

Thanks,