I'm looking at your Xorg.0.log also. I see that Xinerama is enabled so that part is configured correctly.
Looking further along where your Monitors and Connections are being recognized and modules loaded, I see the following:
Code: Select all
76.103] (II) Loading sub module "i2c"76.103] (II) RADEON(0): Output DVI-0 has no monitor section...
76.103] (II) RADEON(0): Output VGA-0 using monitor section Monitor0
[ 76.103] (**) RADEON(0): Option "PreferredMode" "1024x768"
[ 76.103] (II) RADEON(0): I2C bus "VGA-0" initialized.
[ 76.103] (II) RADEON(0): Output DVI-0 has no monitor section...
HTH,
Monsie