If anyone else is having problems with the ATIRadeonX1400 card, the fix is you have to add your Device ID and Vendor to the info.plist in the contents on the kext. My device is listed below your's may be different so check it out before making the changes.

Vendor: ATI (0x1002)
Device ID: 0x7145

Look for 0x71461002 and change it to 0x71451002. You will have to nano the plist using the terminal.
Install OS X with no display drivers selected, go to the System/Library/Extensions folder find the ATIRadeonX1000.kext and make the changes there. Install the kext reboot should work. you will get some mouse tearing but Core/EQ work so DVDs and frontrow should work.

bestman50

Display:

Type: Display
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 128 MB
Vendor: ATI (0x1002)
Device ID: 0x7145
Revision ID: 0x0000
Displays:
Display:
Resolution: 1024 x 768
Depth: 32-bit Color
Core Image: Hardware Accelerated
Main Display: Yes
Mirror: Off
Online: Yes
Quartz Extreme: Supported