[Товарищ ♂uatr]

Удалось найти решение через SqlCommand:

    System.Data.SqlClient.SqlCommand                sqlCommand;
    System.Data.SqlClient.SqlConnection             sqlConnection;
    System.Data.SqlClient.SqlParameterCollection    parameterCollection;
    System.Data.SqlClient.SqlParameter              sqlParameter;
    System.IO.MemoryStream                          memoryStream;
    System.Byte[]                                   bytes;
    ;
    
    sqlConnection = new System.Data.SqlClient.SqlConnection(<connection string>);
    sqlCommand    = new System.Data.SqlClient.SqlCommand('INSERT INTO EXTERNALTABLE ([DATA]) VALUES (@Data)', sqlConnection);
    
    parameterCollection = sqlCommand.get_Parameters();
    sqlParameter        = parameterCollection.Add('@Data', System.Data.SqlDbType::VarBinary);
    
    memStream      = Binary::constructFromContainer(new ContainerClass(<container>).toBlob()).getMemoryStream();
    bytes          = memStream.ToArray();
    memStream.Close();
    
    sqlParameter.set_Value(bytes);
    
    try
    {
        sqlConnection.Open();
        sqlCommand.ExecuteNonQuery();
        sqlConnection.Close();
    }
    catch
    {
        info(CLRInterop::getLastException().ToString());
        sqlConnection.Close();
    }