I think I tried that, now that you mention it, but I didn't like it switching back and forth, so I didn't go that route. I think Tony said that it was an oversight, as to make item appear like that in Arx you can change the current document, without switching it to the active document, but it isn't exposed to .Net, so if you want to P/Invoke I think you can get it without switching the active document.
Thanks for posting your solution Bill.