It’s really easy to create new ftp web site on IIS7.5 with Powershell WebAdministration module.

Import-Module WebAdministration
New-Item IIS:\Sites\"Default FTP Site"\$FTPUserDir\$FTPUsername -Type VirtualDirectory -PhysicalPath "$LogDir"</dir>

$FTPUserDir is the name of the Virtual Directory name. You should use “LocalUser” for standalone machines.