KernelCompile - incorrect instructions for usage of AUTOBUILD

Binary package hint: ubuntu-docs

This is a report about help.ubuntu.com/community/Kernel/Compile.
I didn't just dive in and change it because I wanted to check I wasn't making things worse. If you think I'm right let me know & I'll go fix the page.

I think the information on this page regarding building ubuntu kernels from the ubuntu git repository has some errors. I may be doing some thing wrong but here is what I observe.

I want to build a checkout somewhere between two tags
(eg revision 47309c6a6af8cce3586c735788fc978bbcd7249f.)

Setting the AUTOBUILD variable is supposed to make the build process append a string to the ABI number. Instead of packages like linux-image-2.6.32-25-generic, I should get linux-image-2.6.32-25-47349f-generic.

To make this happen I have to run the build like this:
  fakeroot debian/rules clean AUTOBUILD=1
  fakeroot debian/rules binary-generic AUTOBUILD=1

HOWEVER, doing it as described in the page
  fakeroot debian/rules clean
  AUTOBUILD=1 fakeroot debian/rules binary-generic
does not work, for two reasons.
1. if AUTOBUILD is not set when you run debian/rules clean, the ABI number is not given the extra suffix when debian/control is created. So the kernel build goes ahead but the packaging step fails with an error like this:
        dpkg-gencontrol: error: package linux-image-2.6.32-24-47349f-generic not in control info

2. I find that placing the AUTOBUILD=1 before the 'fakeroot' does not work, neither this way:
     AUTOBUILD=1 fakeroot debian/rules ...
   nor this way
      export AUTOBUILD=1 ; fakeroot debian/rules ...
    Doing it with AUTOBUILD=1 given after the makefile name (debian/rules) does work.

To reproduce:
 * check out the kernel git as per https://wiki.ubuntu.com/KernelTeam/KernelGitGuide
 * run the 'printenv' target of debian/rules with AUTOBUILD set or not set.

Here are my results:
  $ git remote -v
  origin git://kernel.ubuntu.com/ubuntu/ubuntu-lucid.git (fetch)
  origin git://kernel.ubuntu.com/ubuntu/ubuntu-lucid.git (push)

  $ git show
  commit 47309c6a6af8cce3586c735788fc978bbcd7249f
  ...
  $ echo $SHELL
  /bin/bash
  $ fakeroot debian/rules printenv|grep abinum
  abinum = 25
  $ AUTOBUILD=1 fakeroot debian/rules printenv|grep abinum
  abinum = 25
  $ fakeroot debian/rules printenv AUTOBUILD=1 |grep abinum
  abinum = 25-47349f

  $ cat /etc/lsb-release
  DISTRIB_ID=Ubuntu
  DISTRIB_RELEASE=10.04
  DISTRIB_CODENAME=lucid
  DISTRIB_DESCRIPTION="Ubuntu 10.04.1 LTS"