Stop WCF MessageInspector from automatically encoding message to Base64String

Question

I have a class MessageInspector that implemenents IDispatchMessageInspector, and in its BeforeSendReply method I intercept all WCF replies so I can compress the data before the message gets sent. The data is a ByteArray.

The problem is that when I re-construct the message with the compressed ByteArray, WCF encodes the message as a Base64String and then sends it off, is there any way to disable this automatic encoding?

Code:

public void BeforeSendReply(ref Message reply, object correlationState)
{
    if (!reply.IsFault && !reply.IsEmpty)
    {
        //read json
        XmlDictionaryReader bodyReader = reply.GetReaderAtBodyContents();
        MemoryStream ms = new MemoryStream();
        XmlDictionaryWriter jsonWriter = JsonReaderWriterFactory.CreateJsonWriter(ms);
        jsonWriter.WriteNode(bodyReader, true);
        jsonWriter.Flush();

        //compress data
        byte[] ba = ms.ToArray();
        byte[] data = ZLibCompressor.Compress(ba);

        //rebuild and send reply
        Message newReply = Message.CreateMessage(MessageVersion.None, null, data);
        reply = newReply;
    }
}

Reply in browser:

WCF Get reply in Firefox