Ok. It might be incompatible, but there are still a couple things to try.
1: Double check which version of compactflash.device you use (type version compact...) in shell
Use at least v1.27. (If you have 1.32 you could also try downgrading as I once had a card that stopped working when upgrading from 1.27 to 1.32)
2: Make sure it's not an 'activate=no' line in the mountfile that's fooling you.
If this line is there, CF0 will not be mounted until first access, to save ram.
Try simply typing CF0: in shell to check if it comes to life.
3: Read the readme and try the two flags/options described there for non-standard cards.
Good luck!
If it still doesn't work you could always mount the card reader out the rear expansion port
