How can you distribute an INI file with confirmed key?

I need to be able to distribute an INI file with confirmed key.

This is so users can download winscp3 with my custom ini and not have to accept the host key manually.

This is the best reference I have seen:
https://winscp.net/eng/docs/config
and
https://winscp.net/forum/viewtopic.php?t=2236

But neither tell me how to set this up so I can use 'Inno Setup' and package everything together.

Any ideas?

Just like any INI.
Switch to INI-mode, then connect to the site. Accept the key, and it will be saved inside the INI.