It all depends on exactly what you want to do. If you only want to hide the dial, without removing the deltas, or affecting the channel in any other way, again this can be done either with a pose file, or in a cr2 editor. A pose file (pz2) to hide a dial looks like this:

{

version
        {
        number  3
        }

actor [internal name of actor]
        {
        channels
                {
                targetGeom [internal name of channel]
                        {
                        hidden 1
                        }
                }
        }
} 

Note that for a channel that contains deltas, you will need to apply the pose file each time you load the figure. For a more permanent way to hide dials, open the cr2 in a cr2 editor (or text editor), and place the line "hidden 1" just above the closing brace for that channel. The reason "hidden 1" needs to go after the deltas, is that reading the deltas forces poser to display the dial.

P.S. As far as I know, what I have said in this thread relates to all versions of Poser.