I realize this isn't about NSIS, but it has to do with programming. And where do I find programmers? Right.

I have some C++ code with a function (get_blowfish_key) which I need to call from Visual Basic/Delphi.
I already got the DLL to compile, but I can't call the function. Could someone please tell me how to do this?
You can check the project at:
http://www.vdsp.myweb.nl/mixhelp.zip

The function is supposed to be called with a byte array of 80, and return a byte array with 56 items.

Can anyone tell me how to do this properly?