proper way to override dh

I have the following script which auto packages the blender binaries and I would like to get it released to the community.

I would like this to be a single file script so all of the control file changes need to happen in an idempotent method (see current script here http://paste.ubuntu.com/8582394 )

The problem comes from the control file substitution method used on lines: 51, 52 of the script link.

When dh_gencontrol is called to first time in the binary hook, the control file is changed in the DEBIAN holding directory correctly.

This works until the dpkg-genchanges program is run. Sense dpgk-genchanges has no `dh` wrapper, I cannot get the substitution variables to match when processed.

It produces this error in the binary hook (last two lines) -->

dh binary --parallel

dh_testroot -O--parallel

dh_prep -O--parallel

dh_auto_install -O--parallel

dh_install -O--parallel

dh_installdocs -O--parallel

dh_installchangelogs -O--parallel

dh_icons -O--parallel

dh_perl -O--parallel

dh_link -O--parallel

dh_compress -O--parallel

dh_fixperms -O--parallel

dh_strip -O--parallel

dh_makeshlibs -O--parallel

dh_installdeb -O--parallel

debian/rules override_dh_gencontrol

make[1]: Entering directory '/home/surgemcgee/tmp/blender-2.72'

dh_gencontrol -- -DHomepage="http://blender.org" -DDescription="Industry comparable 3D rendeing sofrtware for the advanced hobbiest." -DSection="Graphics;"

dpkg-gencontrol: warning: Depends field of package blender: unknown substitution variable ${shlibs:Depends}

make[1]: Leaving directory '/home/surgemcgee/tmp/blender-2.72'

dh_md5sums -O--parallel

dh_builddeb -O--parallel

dpkg-deb: building package `blender' in `../blender_2.72_amd64.deb'.

dpkg-genchanges -b >../blender_2.72_amd64.changes

dpkg-genchanges: error: package blender has section unknown in control file but Graphics; in files list

dpkg-buildpackage: error: dpkg-genchanges gave error exit status 255

Thanks in advanced for helping, Robert

proper way to override dh_gencontrol