The IDE driver (scsi.device) automatically mounts partitions if it finds some. The compactflash.device does not do this. You have to mount the partition manually, either by creating a mountlist (like the CF0 example from FAT95, but using FastFileSystem instead of FAT95) or by using a program which can mount partitions, for example the Mounter program which comes with OS 3.9.
Bye,
Thomas