*istD Lens Question

[Tom C]

Can a lens without an aperture ring be used on the *istD?  I just tried to 
use my 500mm F8 Mirror lens and could not get the shutter to fire.  I 
thought I was doing it correctly... as when using a non-A lens.  Now I can't 
even find the instructios for how to do that, and I didn't see them 
mentioned on the Pentax USA sight either.

Hawk got away. :(
Tom C.