Sorry, but I think this should work (not tested, I'm on Linux).
code:
var whitelist = Array();
whitelist[0] = "asdf@asdf.com";
// Add more here!
function OnEvent_ChatWndReceiveMessage(ChatWnd, Origin, Message, MessageKind)
{
if(Messenger.MyStatus == STATUS_AWAY || Messenger.MyStatus == STATUS_IDLE)
{
for each(email in whitelist)
{
// Multi-conversations won't work yet.
if(email == ChatWnd.Contacts[0].Email)
{
SendToPHP(email, Message);
}
}
}
}