What's the best timing to implement autoplay in windowless ActiveX plugin?

What's the best timing to implement autoplay in windowless ActiveX plugin?

I have a ActiveX Plugin control (windowless mode).
The question is that is there a function(or a timing) where I can put
customize initialization(implement autoplay) according to property values?
(param name="autoplay" value="true")
I know the Plugin control's properties has been loaded correctly after
IPersistPropertyBagImpl::Load(pPropBag, pErrorLog) is finished:
HRESULT CPluginCtrl::Load(IPropertyBag *pPropBag, IErrorLog *pErrorLog)
{
if (pPropBag == NULL)
{
return E_POINTER;
}
HRESULT hrRetTemp;
VARIANT varProperty;
VariantInit(&varProperty);
VariantClear(&varProperty);
hrRetTemp = pPropBag -> Read(L"windowed", &varProperty, pErrorLog);
if (SUCCEEDED(hrRetTemp))
{
m_bWindowOnly = _wtol((LPCWSTR)_bstr_t(V_BSTR(&varProperty), true));
}
else
{
m_bWindowOnly = FALSE;
}
VariantClear(&varProperty);
return IPersistPropertyBagImpl<CVivoPluginCtrl>::Load(pPropBag,
pErrorLog);
}
, but I think it's a little bit strange to implement autoplay in this
function.
Any better ideas?