Not configuring the kernel from scratch!

[Victor <vdemart@supereva.it>]

Once I've installed a new-brand potato 2.2r2 from CDs, I'd like to rebuild 
the 2.2.18pre21  kernel. 
I know that I can dpkg the source kernel from my CDs and 
then configure and compile it but you know in this case -if you use "make 
menuconfig" - Debian proposes a very basic standard configuration which 
doesn't 
look the same as that installed automatically from the original CDs.
I want to start from the configuration file (.config or 
whatever) which has generated the image contained in the standard 
distribution.
Where can I get this configuration file?
Vittorio