Locked items inside Virtual Population
You can drag the entire group onto the simulation. The surfaces are tagged, and will be assigned to the correct material properties automatically.
The reason for the locks is to prevent users from deleting individual surfaces, or editing them in some way. This would break the poser functionality. If you are bothered by this, or don't need to change the posture of the model, you can always select the bone mesh system and run "Clone As Static" in the context menu.