thanks for the answer, I apologoze for not being so clear:
When the AmiKit (package full of proggies, independent from AF2005) is started for the first time, it asks the user for some source of the AmigaOS files (because these OS files cannot be part of the AmiKit's archive, ofcourse). Therefore the user has to insert her/his original AmigaOS3.9 CD (or 3.5 or XL or AF2005 CD) and the OS files will be copied to Amikit. From this point the AmiKit is fully functional and independent filesystem.
Like I said, I'd like to support AF2005 Online Edition (that doesn't come with a CD) as a source of OS files for AmiKit...
So once I know where AF2005 is installed (via %AMIGAFOREVERDATA% variable) I use AmigaDOS script that copies these files from PC side to AmiKit's filesystem. The only problem is that the PC variable consists Windows-like backslashes. I need to convert them to Amiga slashes, so I can use this path with AmigaShell.