Peteho,
I am also wondering about these types of adapters and found one from Pretec that claims to allow what you would like (i.e., using your SM cards in your PDA's CF slot).
Actually, I am also interested in using this adapter for a CF digicam (i.e., using my old SM cards in a CF-based camera), but when I emailed one of its distributors here in Canada, I was told that the CF compartment door on the camera would not be able to close with the adapter inserted.
PRETEC adapter