When I log out and back in, the volume reset itself back to mediu. I use the netbook's Fn buttons to rise the volume instead of the volume plugin, because of the bug I just reported.
The volume plugin itself does not store any volume levels. This is part of either alsa or pulseaudio. Alsa levels usually are saved and restored in init scripts during shutdown and starting of your computer. Pulseaudio has a more sophisticated mechanism (which might change something session related), but in any case the razor volume just reads the current volume provided by alsa or pulseaudio, whenever it gets initialized.
In my opinion this should not be part of the mixer application, as you might wanna use multiple ones which will confuse the store/restore step.