This was possible on the older Android based OS versions, but I cannot find the setting anywhere in the CE based versions. I also cannot find it in any of the user guides for the CE version, however, this release notes page from Cisco says that it is a feature.
The datasheet you provided the link to only shows this as a feature for the android software version.
It was a feature with Android because you could use it to check email and things like that (just like a smartphone), you can't do that with CE code so the PIN isn't necessary. Think about it - it's just a video phone with a big display, right? You don't lock desktop phones with PIN's.
Hope this helps!
Oh I see.
The reason we want to have a PIN is because we use these for our remote users at their home offices. Some of them have young children, and we don't want them to accidentally place calls on the device.
Unfortunately, that is not a feature that is available in the current CE code. If you think it is something that should be added, your best point of contact would be your local Cisco Account Manager who could log a Feature Request for you to be evaluated and, if approved, implemented in a future software release.