ISPConfig 3 is very portable and as PHP is working fine on Linux and windows, the ispconfig interface will work without modifications on IIS too. The backend, which does the configuration work is implemented as a set of plugins, also written in PHP for easy portability and to enable support for a wide variety of http and mail daemons.
I'am not familar with the way a Exchange server can be configured by a script, but if its possible that you do the configuration of a exchange server from a php script e.g. by running the ispconfig server part in phalanger http://www.codeplex.com/Wiki/View.as...Name=Phalanger
if you have seome .net bindings or by using the com extension from the "normal" php or by accessing some kind of configuration database or files it should be possible. The server part is basically a script that runs every minute which first loads the plugins for the current system and then does the configuration work based on events. So the main work in porting would be to implement some plugins for IIS and Exchange and write a new installer.