Etch and beyond: How to keep initrds able to mount encrypted drives?

[Bradley Alexander <storm@tux.org>]

I just built a fresh etch box, workstation build. I encrypted everything but /boot using lvm. My goal is a sid box, but I've had to go through several iterations of the etch install. First, I found that the installer/initrd did not like having multiple physical volumes on the root volume group. 

Then I found that upgrading the kernel (or even an automatic upgrade of it) writes a new initrd, which does not include the encryption. I have always rolled my own kernel, so I don't have much experience with initrds or update-initrd. Can someone tell me how to configure it so that update-initrd has the correct files to make sure that even between kernel upgrades, the proper files are getting written?

Thanks,
--b