How does an apt-cacher user select his debian mirror?

[andreas.koenig.gmwojprw@franz.ak.mind.de (Andreas J. Koenig)]

Today I tried out the current debian installer "testing-i386-netinst"
(daily build) on my tiny network where I have a server running
apt-cacher. This means that the address is not one of the official
mirrors.

I could not figure out what I have to enter to use that apt-cacher
box. There was the option "enter manually" but I didn't see any help
that helps me figure out what I should type in. After several tries I
gave up and used the official German mirror.

What should I enter?

Thanks!
-- 
andreas