Serial port write buffer

I'm writing to some serial comm port with specific bytes set into buffer. My protocol for write buffer is written below. Platform is Windows and IDE is Visual C++.

1. Byte 0 will have message type indicator (Byte)
2. Byte 1-4 will have message number (Uint32)
3. Byte 5-8 will have unix epoch time (Uint32)
4. Byte 13-14 will have number of sample packets (Uint16)
5. Bytes 15+ (upto 60) will have sample data packets (Uint16)
6. Byte 15+(No of samples*2) will have end of message (Byte)

Now I'm concern about buffer building (raw Bytes) from integer or short values.

void ConvertIntToByte(int iValue, BYTE* ucRawBuffer, int iOffset)
{
  ucRawBuffer[iOffset]   = ((iValue >> 24) & 0xFF);
  ucRawBuffer[iOffset+1] = ((iValue >> 16) & 0xFF);
  ucRawBuffer[iOffset+2] = ((iValue >> 8) & 0xFF);
  ucRawBuffer[iOffset+3] = (iValue & 0xFF);
}

void ConvertShortToByte(short iValue, BYTE* ucRawBuffer, int iOffset)
{
  ucRawBuffer[iOffset]   = (iValue >> 8) & 0xFF;
  ucRawBuffer[iOffset+1] = iValue & 0xFF;
}

void DataThreadFunction()
{
  while(!m_bClosed)
  {
    DWORD dwRet = WaitForSingleObject(m_hDataSendEvent, INFINITE);
    if(dwRet == WAIT_OBJECT_0)
    {
      ResetEvent(m_hDataSendEvent);

      int iUTCTime = GetEpochTime();
      m_iMsgSequence++;
      ASSERT(m_iMaxSamples != 0);

      BYTE ucXmtdat[60] = {0};
      ucXmtdat[0] = 0x0B;
      ConvertIntToByte(iUTCTime, ucXmtdat, 1);
      ConvertIntToByte(m_iMsgSequence, ucXmtdat, 5);
      ConvertIntToByte(m_iMaxSamples, ucXmtdat, 13);
      int iOffset = 15;
      // m_data - member vector populating from some other method
      for(unsigned int i = 0; i < m_data.size(); i++)
      {
        short iCurrData = m_data[i];
        ConvertShortToByte(iCurrData, ucXmtdat, iOffset);
        iOffset += sizeof(unsigned short);
      }

      m_data.clear();
      iOffset = 15+(m_iMaxSamples*2);
      ucXmtdat[iOffset] = 0xCA;

      bool bSuccess = m_objComm.WriteCommPort(ucXmtdat, 60);
    }
  }
}