I use a bridge for my sling box. I use wireless n router as a wireless bridge as well. I think I learned all the lessons thru trial and error and have my set up solid for about a year now. When you run the setup assistant and the sling is on a bridge the setup assistant's broadcast is not sent past the bridge to the sling. So connect the sling to the router then run the setup. Make sure you manually configure the sling, no need to change any settings, just click next all the way. That sets the sling to a static ip. You can then place it on the bridge and go.
The reason every thing else works on the bridge is because its all outbound traffic.
If you don't want to do that there are other options.
1. Staticly set the bridge to a ip
2. Some bridges allow you to clone the mac address clone it to the sling mac address.
3. When the sling has a solid network light log into the router and see what ip it has. If you ping the ip then run the setup assistant it will show up.