Well, since SanDisk is not going to reply, I tried with the default 5V setting the DeLock adapter I mentioned earlier with very old, 0.5G CF card SanDisk SDCFH. It does support PIO 4, but no DMA and the speed is very slow:
Tested on ASRock 775Dual-VSTA (P4, 3.8GHz WinXP, alligned). Also works...