Checking out previous revisions

Hello,

I'm trying to open previous revision changes to a design but all I am able to checkout is my latest version.

Steps that I currently doing (which obviously isnt correct):

My Vault...

     Project

          Assembly Design (right click)

               Open Document

                         (at this point I've tried several different combinations of the options and get references. I also clicked the drop down menu for the revisions and selected a previous revision but when I check out the part the part that opens always ends up being the last check in I saved.

Thanks!

SolidworksWorkgroup Pdm