System-specific qt version paths are saved in roaming user profile

I work with two systems (Windows 7) using a roaming profile. On system A, Qt is installed on the C drive. On system B, Qt is installed on the E drive. If I set up the correct path to Qt on system A, the settings are saved to the user registry, which roams to each machine I log into. So when I log into system B, the add-in complains that it can't find Qt on the C drive. If I change it on system B, it also affects system A! I find myself having to change this every time I switch machines, which is often enough to cause great annoyance.