Hi Dogbreath, what SW load was installed when you last tested this? If I remember well before MCD 4.0 (or so) you had to use two IP device licenses a one User license to enable hotdesking, one IP device for the hotdesk device itself and one IP device and one user license for the user that was logging on. With this configuration it was possible program the keys on the logged of device.
But after Mitel simplified the user and device licensing and after introduced device service levels, devices that has Trusted level do not allow to program the keys. For hotdesking you would then just need one "IP user" license but you lost the possibility to setup keys for sets when the user if logged off.