The ICIPermissions interface represents the permissions for folders. Obtain it by using the GetFolderPermissions method of the ICISite interface. You can also use the GetBlankPermission method to start with no permissions. (Refer to Site VFS Folders for details of ICISite methods related to the VFS.)
aPerm = s.GetFolderPermissions("\pub\")
Set p = s.GetBlankPermission("\pub\", "Administrative")
Changing properties in the IPermission interface has no effect until you call the ICISite SetPermission method.