I tried it at a very low idle as well as higher RPM.  No go, but then I didn't know the trick of reversing the control.  I just found a video on You Tube about the same issue on a CASE 580K backhoe.  
  It shows the guy reversing the control at the last minute to latch the lock, although the lock is a different design.  I went out to try it after I saw the responses to my post.  It had just finished raining and the mosquitos were vicious.  I came back in the house and will try again tomorrow.  I did notice one thing, however.  A bird got inside the cab somehow and splashed white sh** all over the seats and engine.  I have the doghouse removed so the bird must have gotten in that way.