protected static int GetUInt64(byte[] Data, ref UInt64 Value, int Pos)
{
byte[] ValueData = new byte[sizeof(UInt64)];
Array.Copy(Data, Pos, ValueData, 0, sizeof(UInt64));
// flipping the Array .... Big Endian ..
ValueData = FlipArray(ValueData);
Value = BitConverter.ToUInt64(ValueData, 0);
return Pos + sizeof(UInt64);
}