The VBox will "work" with the corotor, but you'll have a problem if you're using the two RG6 cables. Diseqc commands will get sent down the active RG6 cable.
I'm not sure what a Viewsat Rx is, so I cannot comment on that much. However, if you can utilize a diseqc switch from this receiver and still control the rotor, then you could run one cable through from the receiver, to the vbox, and then one cable out of the vbox. Then you'd split from the one cable to 2 cables coming out of a diseqc switch in order to connect to both lnb on the corotor.
hopefully someone will come along and clarify this concept a bit more than I can think to do at this time, if you still have questions.