private MemoryStream ProcessMemoryStream(Stream inputStream, bool dispose)
    {
        StreamWriter xmlStream = null;
        var outputStream = new MemoryStream();
        bool continueFilter = false;
        try
        {
            xmlStream = new StreamWriter(outputStream);
            using (var reader = XmlReader.Create(inputStream))
            {
                using (
                    var writer = XmlWriter.Create(xmlStream,
                        new XmlWriterSettings() {ConformanceLevel = ConformanceLevel.Auto}))
                {
                    while (reader.Read())
                    {
                        if (reader.LocalName.Equals("SignatureConfirmation") &&
                            reader.NamespaceURI.Equals(
                                "http://docs.oasis-open.org/wss/oasis-wss-wssecurity-secext-1.1.xsd"))
                        {
                            if (!reader.IsEmptyElement) continueFilter = reader.IsStartElement();
                        }
                        else if (reader.LocalName.Equals("Signature") &&
                                 reader.NamespaceURI.Equals("http://www.w3.org/2000/09/xmldsig#"))
                        {
                            if (!reader.IsEmptyElement) continueFilter = reader.IsStartElement();
                        }
                        else if (continueFilter)
                        {
                           // continue to next node
                        }
                        else
                            XmlHelper.WriteShallowNode(reader, writer);
                    }
                    writer.Flush();
                }
                reader.Close();
            }
            outputStream.Position = 0;
            return outputStream;
        }
        catch (Exception ex)
        {
            // handle error
            throw;
        }
        finally
        {
            if (xmlStream != null && dispose) xmlStream.Dispose();
        }
    }

internal static class XmlHelper
{
    internal static void WriteShallowNode(XmlReader reader, XmlWriter writer)
    {
        if (reader == null)
        {
            throw new ArgumentNullException("reader");
        }
        if (writer == null)
        {
            throw new ArgumentNullException("writer");
        }

        switch (reader.NodeType)
        {
            case XmlNodeType.Element:
                writer.WriteStartElement(reader.Prefix, reader.LocalName, reader.NamespaceURI);
                writer.WriteAttributes(reader, true);
                if (reader.IsEmptyElement)
                {
                    writer.WriteEndElement();
                }
                break;
            case XmlNodeType.Text:
                writer.WriteString(reader.Value);
                break;
            case XmlNodeType.Whitespace:
            case XmlNodeType.SignificantWhitespace:
                writer.WriteWhitespace(reader.Value);
                break;
            case XmlNodeType.CDATA:
                writer.WriteCData(reader.Value);
                break;
            case XmlNodeType.EntityReference:
                writer.WriteEntityRef(reader.Name);
                break;
            case XmlNodeType.XmlDeclaration:
            case XmlNodeType.ProcessingInstruction:
                writer.WriteProcessingInstruction(reader.Name, reader.Value);
                break;
            case XmlNodeType.DocumentType:
                writer.WriteDocType(reader.Name, reader.GetAttribute("PUBLIC"), reader.GetAttribute("SYSTEM"),
                    reader.Value);
                break;
            case XmlNodeType.Comment:
                writer.WriteComment(reader.Value);
                break;
            case XmlNodeType.EndElement:
                writer.WriteFullEndElement();
                break;
        }
    }
}