You can't. The chip/magnet in "official" accessories is what triggers the additional functions. Maybe some third party accessory makers have figured out how to replicate it but if yours hasn't there's not much you can do.
This is what's added to accessories when the device detects the official S View cover...
you can try the "gravity screen" app. I used it to auto turn off the screen when I put the phone in my pocket and auto turn on when i pull it out. It relies on the proximity sensor to do this but I don't see a hit battery-wise