Fundamentally I do not understand your question. You may need to restate it.
Anyways, You don't have to install anything for Slingbox to work with a device. Slingbox simply takes the video and audio feeds from a device such as an Apple TV and sends them over the net. A person can control that device over the net because the Slingbox also has an IR controller that attaches to the devices IR receiver.
You probably already knew that. I have a slingbox and it works just fine with the Apple TV. But from what I gather from your post- you use Slingplayer to connect to your friends slingbox. and you have an Apple TV... and you want to ??? I'm not sure what you want to do but if you want it to be able to send its media over the internet like you do with slingbox, you'll have to go buy a slingbox for it to work. There's no software only solutions that I'm aware - even with a hacked Apple TV.