preserve environment does not work

Binary package hint: sudo

In previous Ubuntu versions, a command like "sudo su -p -" switched to the root user, but preserving the environment, like the $HOME variable. In Natty, this doesn't seem to work. sudo alone and su alone can be convinced to preserve the environment, but the combination of sudo su doesn't seem to work anymore. Reading the man pages suggest me I'm doing everything right, but I cannot achieve becoming root, while preserving my environment.

The same commands on Lucid work like a charm.