I need to serialize a class which contains an `StorageFile` (a class which cant be serialized) as an attribute. Although I tagged that attribute as `[IgnoreDataMember]` the `XmlSerializer` keeps tryng to serialize it, what isn't expected.

An snippet to clarify the issue:

```
[DataContract]
public class Attachment
{
    [DataMember]
    public string FileName { get; set; }

    [IgnoreDataMember]
    public StorageFile File { get; set; }

    [DataMember]
    public Boolean UserCreatedContent { get; set; }
}

```