Can a Barlow lens be used with my Regal F-ED spotting scope?

The Regal series of spotting scopes have removable eyepieces and take 1.25 in barrel-diameter oculars.

Even though a 1.25 in Barlow and eyepiece will fit into the scope, the design of the focuser on the Regal scopes does not allow infinity focus when using Barlows.

Updated 12/18/13