The InstallIt server-side is divided into two main parts:
The main server is defined in the default settings of each copy of InstallIt. This way other companies may use InstallIt for company-internal software repositories or whatever. On this server, only one file has to exist: /mirrors.xml This file contains information about available servers (sharing the same repository) and may also be placed on one of them (which combines both parts (main server and mirror), then.
Mirrors are, of course, harder to set up than the main server. However, the structure is very simple.
There has to be a file /packages.list containing a list of the available package header files (see 2. for information about them). Those files have to be listed with their basenames (so, no relative or absolute paths, only the filename). It could e.g. look like this:
dbh-1.0.24-Source exo-0.3.0-Portage exo-0.3.0-RPM exo-0.3.0-Source libxfce4mcs-4.2.2-Source libxfce4util-4.2.2-Source
Package headers are stored in the /Packages folder. They are seperated from the actual package files, which are placed in /Files.
/mirrors.xml
/packages.list /Packages ... /Files ...