AA is automatic mode. The flash uses a built-in sensor to adjust the flash power. TTL (through the lens) uses the camera metering to adjust the flash power.
Use TTL-BL mode if you want to balance the flash with ambient light. Up the ISO will help.
If you want full control, use manual exposure (M mode). Meter the ambient light. Keep it within 2 stops from the "correct" exposure by adjusting shutter speed/aperture. (Use the metering indicator in the viewfinder to do that.) Raise the ISO if you need to. Set the flash to TTL or TTL-BL mode. You should get some ambient light in your photo. If you want the background to be total black out, the metered value of the background should be >3 stops below (increase shutter speed or reduce the apperture and ISO).
BC