rebuilding kernel rpms

[Ken Teh]

A simple question:  I'd like to rebuild the current kernel rpm with minor 
mods to the config.  The procedure I'm following is what's documented for 
RHEL 4, that is,

install the src.rpm
do an rpmbuild -bp
cd to /usr/src/redhat/BUILD/kernel-<vers>/linux-<vers>/
make menuconfig
to create the custom .config.  At this point, how do I fold the .config that 
I generate back in so I can simply say 'rpmbuild -ba' and have it generate 
the kernel rpms with my mods?

Thanks!