GZipStream over .NET webservice causes invalid character issue

I'm working on a complex .NET client server architecture customization and I absolutely have no control over request/reply sent or received except that I can add my stuff to the request/reply objects.

I've a dataset on server side to be sent to client andI'm using GZipStream to compress the dataset. The compression works fine, but when the reply is received on client end, I get invalid character exception - 0x1F. I googled and could not find appropriate resource to address开发者_如何学运维 this issue.

Compression code:

Private Function Compress(ByVal data() As Byte) As Byte()
        Try
            '---the ms is used for storing the compressed data---
            Dim ms As New MemoryStream()
            Dim zipStream As Stream = Nothing

            zipStream = New GZipStream(ms, _
                            CompressionMode.Compress, True)
            '---or---
            'zipStream = New DeflateStream(ms, _
            '                CompressionMode.Compress, True)

            '---compressing using the info stored in data---
            zipStream.Write(data, 0, data.Length)
            zipStream.Close()

            ms.Position = 0
            '---used to store the compressed data (byte array)---
            Dim compressed_data(CInt(ms.Length - 1)) As Byte

            '---read the content of the memory stream into 
            '   the byte array---
            ms.Read(compressed_data, 0, CInt(ms.Length))
            Return compressed_data
        Catch ex As Exception
            Return Nothing
        End Try
    End Function

Any idea to fix this issue considering the fact that I can alter the request/response handling mechanism is really appreciated. In addition, I also request any ideas on better ways handling large dataset transfers over webservice. Thank you.