Option 1: use a custom tarball which includes those modules. In that case, the custom tarball will have a file install.xml in its root directory, so that installing OpenACS normally will produce a simulation server.

Notes on custom tarball creation:

mkdir -p /tmp/tarball/
cd /tmp/tarball
cvs -d :pserver:anonymous@openacs.org:/cvsroot export -D 01/01/2010 acs-core
 cvs -d :pserver:anonymous@openacs.org:/cvsroot export -D 01/01/2010 openacs-4/contrib/packages/simulation openacs-4/contrib/packages/bcms openacs-4/packages/notifications openacs-4/packages/acs-mail-lite openacs-4/packages/workflow  openacs-4/packages/file-storage
mv openacs-4/contrib/packages/simulation/ openacs-4/packages/
mv openacs-4/contrib/packages/bcms/ openacs-4/packages/
cp openacs-4/packages/simulation/install.xml openacs-4/
mv openacs-4/ openacs
tar cz -f openacs-with-simulation-phase-1-final.tar.gz openacs

Option 2: Install acs-core, and then rely on the automated install to do the rest. Go to /acs-admin/install/install and install simulation. The rest should happen automatically.