This code sample explains how to add/update or remove File Manager.
SiteForUpdate site = new SiteForUpdate();
site.webhosting = new WebHosting();
//Add file manager
filemanager fmConfig = new filemanager();
fmConfig.Enabled = true;
// To remove set to false
site.webhosting._filemanager = new filemanager();
site.webhosting._filemanager = fmConfig;
//General details
site.DisplayName = "mysite.com";
site.ContactName = "ABC";
site.ShortName = "mysite.com";
site.ContactName = "0132465798";
site.ContactEmail = "blackhole@ensim.com";
site.AdminDisplayName = "Administrator";
site.AdminUserName = "admin@mysite.com";
site.AdminPassword = "ensim123";
site.AdminEmail = "user@example1.com";
//Service Details
site.webhosting.Enabled = true;
site.webhosting.IsIpbased = true;
site.webhosting.BandwidthQuota = 1024;
site.webhosting.BillingCycleStartDay = 1;
site.webhosting.BandwidthActionSendMail = true;
site.webhosting.BandwidthCapped = false;
site.webhosting.DiskQuota = 25;
site.webhosting.MaxUsers = 5;
//Call update method
w.UpdateSite(site, "admin", "ensim123");