Create a folder with the contents you want on your ISO.
Open Disk Utility and use the New Image from Folder menu item to create an image. Make sure it is uncompressed and use the CD/DVD master option.
Select ExFat format.
Save. Now add your files in finder for that image. eject.
Open the Terminal
Assuming your new image is called ~/Desktop/drivers.cdr (the file is on your desktop and called drivers.cdr) type:
hdiutil makehybrid -iso -joliet -o drivers.iso drivers.cdr
This will create an ISO/Joliet .iso file.
now you can use this iso as windows drivers disc over a kvm-ip connection 🙂