Compact Flash adapters
try the following program:
gogle for: GParted Live Disk
With this tool, you should be able to make TWO PARTITIONS on your 1GB CF-card (cheaper then 512MB) and create a partition with 510Mb (caution! NOT 512Mb!!).
Now you should be able to use the CF-card in your SPD-S.
Further advantage, you can store backups on the second partition, by copying them (on your PC) to the second partition.