8.0RC custom kernel not installing?

[LoH]

I compiled a custom kernel with ZFS enabled and installed it. Everything 
appeared to work fine, then I realized that I needed to make some more 
modifications (ALTQ, disabling ulpt). I made those configuration changes 
to the existing ZFS kernel config.

After running
make buildkernel kernconf=ZFS
and
make installkernel kernconf=ZFS

(ZFS is the name of the kernel config file)
I rebooted the machine but didn't see any change in the system config. 
I've also made sure I did the build/install as root.

I doubled-checked the config in the kernel directory, the config is 
properly done.

Any ideas?

--Joseph