Pelikal
I've just been on the Microtek site, and the Windows XP driver listed there appears to include an undocumented 64-bit Vista driver
If you download the file and install it under compatibility mode for Vista it may just work
Alternatively unRAR the setup file (its not a real .exe, but a self-expanding RAR) and then manually run the setup files from \disk1 of the expanded file. There are TWO setup files, setup.exe and setupinf.exe
If one doesn't work then try the other - again under compatibility mode.
And if that still won't work, simply use the plug n play driver find routine from within device manager to pick up the .inf file in disk one
ftp://microtek:[email protected]_v6_32_ad.exe