scp asks for host key during /etc/init.d

[Guillaume Dargaud]

Hello all,
I have a system that needs to download a file right after boot, so I setup a small service in /etc/init.d/S89getfile that 
does a simple:
scp -p -i /etc/dropbear/dropbear_dss_host_key user at remote:Config.ini /root/
But upon boot I see a message about the key not being in the trusted host file and would you like to add it, which fails 
since there's not even a keyboard on that system.

If I run that exact same script after I login, it runs fine so I know both files /root/.ssh/known_hosts and 
authorized_keys are setup properly. There's only one user (root).
Is it possible that during the boot sequence scp doesn't look in the right place for the trusted host file ?

I tried adding -y but that's an shh, not scp option.
I also tried -o"-y" without success.
Would this work:
-oStrictHostKeyChecking=no

Thanks.
-- 
Guillaume Dargaud
http://www.gdargaud.net/