Eyvind,
You can use the Platform API to communicate the "traditional" way using SendMessage or PostMessage for which there are lots of examples on MSDN. You will have to override the forms WndProc and filter the incoming messages - not as easy as a COM wrapper but it works well.
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
}
Regards
Neil