How to preseed the d-i question "whether to use a mirror"?

[Shachar Or <dawnlight@lavabit.com>]

Hello!

I've this:

 ### Mirror settings
 # If you select ftp, the mirror/country string does not need to be set.
 #d-i mirror/protocol string ftp
 d-i mirror/country string enter information manually
 d-i mirror/http/hostname string mirror.isoc.org.il
 d-i mirror/http/directory string /pub/debian
 #d-i mirror/http/proxy string

in my preseed file and d-i still asks me whether I want to use a mirror. How 
can I preseed this question?

Love.
-- 
Shachar Or | שחר אור
http://ox.freeallweb.org/