Sheepshaver on an intel mac

Does anyone know how to unlock the virtual hard disc in the Sheepshaver virtual desktop?

I'm running Sheepshaver 2.3 under OSX 10.4.9 on a MacBook Pro.

I have to boot from my OS8.5 CD as the virtual hard disc won't boot or save changes to the Startup Disc control panel.

I have already made sure that the disc image in OSX 10.4.9 is unlocked, but the lock must be elsewhere.

Thanks in advance

IM