As I pointed out in my recent blog post that was titled "FTP 7.5 and WebDAV 7.5 have been released", one of the great new features of the FTP 7.5 service is extensibility. In that blog post I mentioned that I wrote the following walkthroughs to help developers get started writing providers for the FTP 7.5 service, and these walkthroughs are all available on Microsoft's learn.iis.net Web site:

We have also recently published the FTP Service Extensibility Reference on Microsoft's MSDN Web site, and here is a list of all the reference topics that we have written for FTP 7.5 service extensibility:

I hope this helps!