Disabling WiFi sleep mode when screen goes off (wm6.1)???

[devicemanager]

Would this work when streaming satellite music too via cellular? I always hated that the backlight would stay on the whole time. I have lowered it but still, 4 hours of streaming doesn't leave much of a battery life for anything else. I have 2 batteries but still wish there was a way to shut the screen off without killing the apps.