Distributable VM that is immutable

[epimic]

I'm trying to create an immutable disk image that is distributable to others. My thought was to create a disk image and then export to an .ova file for distribution. So my process is to create the image, install guest additions, make it immutable and then export to .ova. The problem is that when the .ova is imported, it is now a normal image. What happens to the immutable image? I'm working with VirtualBox 4.1.20 Windows XP guest and Windows 7 host and a .vmdk file. Is there a better way to do this?

[epimic]

After doing some more research, it looks like "export appliance" might be sort of a deprecated way of distributing a virtual machine. I'm now going with copying the .vbox and .vmdk into a .zip file and distribut the .zip file. That way I end up with an immutable disk with guest additions installed. Problem solved.