I am not sure but, you can provide an interface where your admin user can provide the resource value and using ResourceWriter class you can achieve this.
System.Resources.ResourceWriter rw = new System.Resources.ResourceWriter("English.resources");
rw.AddResource("ResourceKey", "Value");
rw.Generate();
rw.Close();
WWW, WCF, WWF, WPF, WFC .... WTF