CComSafeArray<BYTE> arr;
arr.Add(0x00);

const byte zero = 0x00;
arr.Add(zero);

HRESULT Add(_In_ const T& t, _In_ BOOL bCopy = TRUE) // 0x00 as zero for t

HRESULT Add(_In_ const SAFEARRAY *psaSrc) // 0x00 as NULL for pasSrc

CComSafeArray<BYTE> arr;
arr.Add((const BYTE&) 0x00);