How to setup a trivial archive
The "trivial archive" lacks support for apt-pinning and modern secure APT due to the collision of 2 types of Release files. (e.g., old "Debian Reference (sarge)" and "APT HOWTO (sarge)")
You need dpkg-scanpackages which is in dpkg-dev.
Add this line to /etc/apt/sources.list
deb file:/path/to directory ./
Create a directory for the deb files. (For example /root/deb)
export REPO=/root/deb mkdir $REPO
Then every time you put new files in the directory, you'll have to scan the directory and update aptitude.
cp *.deb $REPO cd $REPO dpkg-scanpackages . | gzip > Packages.gz aptitude update
Then you can install the package.