Quick Answer: You can't.
For details see my post on the Raspberry Pi forums.
EGL on the RPi doesn't use the linux framebuffers at all, not fb1 nor fb0. The graphics hardware works at a higher level (dispmanx), the display is made up of multiple layers, when linux starts it creates one layer to cover the full screen for fb0. When you create a window with EGL you also create a new layer and tell the hardware to show it in front of the others.