wget http://nl.archive.ubuntu.com/ubuntu/pool/main/l/linux-source-2.6.20/linux-source-2.6.20_2.6.20-15.27_all.deb
dpkg -i linux-source-2.6.20_2.6.20-15.27_all.deb
cd /usr/src/
tar xvf linux-source-2.6.20.tar.bz2
cd linux-source-2.6.20
cp -iv /boot/config-2.6.20-15-generic .config
sed 's/^EXTRAVERSION = .3-ubuntu1$/EXTRAVERSION = -15-generic/' -i /usr/src/linux-source-2.6.20/Makefile
And you should be all set to reconfigure and recompile the kernel and/or modules that was included with the original Kubuntu-7.4 as lmce 0704 uses it.