$ mkdir -p /path/to # new empty directory
$ cd /path/to
$ tar -xvzf /path/from/gentoo-1.0.2.tar.gz # get source
$ cd gentoo-1.0.2
$ dh_make -e name@domain.dom -f /path/from/gentoo-1.0.2.tar.gz
... Answer prompts.
... Fix source tree
... If it is a script package, set debian/control to "Architecture: all"
... Do not erase ../gentoo_1.0.2.orig.tar.gz
$ debuild
... Make sure no warning happens.
$ cd ..
$ dupload -t nm_target gentoo_1.0.2-1_i386.changes