OK... I broke my promise - couldn't do the tests last weekend. Sorry.
Guys, I checked the delphi code, and apparently there's no different interface to the IDE drives, all is handled by DiscIdCalcDLL.dll. I also tried to remove that backslash, no success.
As I said before, the function "AspiInstalled" works fine. It's returning 5, which is exactly the number of ASPI hosts reported by ASPICHK.exe (Adaptec's tool).
Any other ideas? Maybe writing the code in C and using Inline?
At this point, actually, I'm about to change focus. If you can show me some way of reading an audio CD's TOC (in Win32) I think I can get what I want.