SL5 initrd.img

[Mark Stodola]

Is there a resource/information/script on generating the initrd.img used 
in the SL5 installation media?  I'm trying to inject kernel-lt from 
ELrepo in place of the usual one.  Replacing vmlinuz is easy, but I'm 
not sure where to start getting the initrd updated with the appropriate 
kernel modules.

I already know how to unpack the initrd, but I'm unsure how/where the 
modules included in it are selected, gathered, and supporting files created.

-Mark