File Upload: Show additional column

Hello,

I want to show the creation date of the uploaded file in the editor, but i only get "undefined | filenameXY.txt"

.

{
    label: "Lizenzdateien:",
    name: "CMDB_Asset_License_File[].id",
    type: "uploadMany",
    display: function(fileId, counter) {
        return '<a href="' + editor.file('CMDB_Asset_License_File', fileId).WebPath + '">' + editor.file('CMDB_Asset_License_File', fileId).DateCreated + ' | ' + editor.file('CMDB_Asset_License_File', fileId).Filename + '</a>';
    },
    noFileText: 'keine Dateien'
},

My sql table has following columns: id | Filename | Filesize | WebPath | SystemPath | DateCreated
the field DateCreated has as standard "CURRENT_TIMESTAMP".
Uploading a file works fine.