Add subfolders and items into subfolders

[Anthorn]

Im trying to add a subfolder to a existing folder in the root directory. But instead of appering in the folder, the subfolder appears in the root directory.

My code:
new_row = list.Row()
new_row.ContentType = 'Folder'
new_row.Title = name
new_row.BaseName = name
new_row._EditMenuTableStart = name
new_row.EncodedAbsUrl = self.complete_url+ "/" + url + "/" + name
new_row.ServerUrl = self.site_url +"/"+ url + "/" + name
new_row.LinkFilenameNoMenu = name
new_row.LinkFilename = name
list.append(new_row)
list.save()

Is this feature not implemented or am i doing something wrong here?