When asked for the maker of your unit, click on the link to "supported devices". A new page will come up that has four pulldown menus.
Set the first pull down to "PVR"
Set the second to "Expressvu"
Set the third to "Other"
Set the fourth to "Code1"
Good luck...hope this saves you from all the trial and error required to find it. It would have helped if Slingbox had named it Bell Expressvu instead of "just" Expressvu...I never would have found it except for some browsing I was doing to find Echostar...ah well, all is well that ends well.