Help needed in adding package to package.mask

[dunsurfin]

I'm trying to add app-arch/q7z-0.7.1 to etc/entropy/packages/package.mask to stop entropy trying to remove it on each update. I managed to add app-emulation/virtualbox-bin-2.1.2 without any problem and it shows up in Spritz but q7z is playing hard to get. Any suggestions gratefully received.