The current version of the Business Solutions Pack installer does not provide any mechanism by which you can specify the applets to be installed. This is a feature we plan to add to the next release of the installer.
I understand other sites using ZEN to roll out applets first install the applets to a local machine, remove those they don’t want, and finally build a ZEN snapshot.
If you are using eDirectory, another option would be to distribute the applets using the Directory itself. See the Distribution Kit documentation for more information.