Maybe you not fully understand frontpage for linux. This package has been made available by microsoft but it does not really integrates itself into linux. If you use frontpage with FTP in the same website it will mess up your permissions. ISPConfig supports frontpage because some poeple needed it, but this does not mean that we have to provide howtos for that. You are free to write a howto on that topic when you finished your installation.
I've installed frontpage on a debian box some time ago and it took me about a day or more to get it working. Mabe the better solution might be to remove the frontpage support from ISPConfig at all.