I was in the BG last night and I found out a way to get rogues even when stealthed but you can only do it with a warlock.
If you have your succubus out, get ready to use suduction. Now it does not matter how far the rogue is away as long as you can atleast see him once. If you see a rogue then suduce him and even if he goes stealth the deamon will still go after him and stun him. Hope this helps