I have a FreeBsd template which I want to customize. From what I see automatic guest customization is not supported"
Automatic guest customization is not supported on this Guest OS type. The settings on this page will be passed to the Guest OS.
You can use custom scripts to configure the Guest OS. Refer to documentation for details.
From the above message I understand that the settings are passed somehow/somewhere to the OS. Where excatly can I find them? or how to use them in my custom scripts?