You need Windows Installer 4.5 pre-installed along with .net 3.5SP1 otherwise those will apparently get triggered non-silently. My test image PCs already come with both installed, so I had no way of testing this.
You don't need to supply the serial during the installation (if you don't want to). You might want to get rid of the Yahoo Plugin (as it's beeing bloked by some anti virus products) you can do this by supplying "remove=YahooCCM" in the MSI part of the commandline.
I use this commandline for installation:
setup.exe /v"addlocal=all Remove=YahooCCM /qb-!" /L1030
(L1030 is by the way for Danish language)