Transfer Object via Drag Drop

[Reiner]

Now after one Month search in Google and Forums i get crazy. Everybody
transfers only Text or Pictures.
Heeeeeeeeelp.
I need Drag one ListItem from a OCX Control (My own Control in ATL c++
derived from CListCtrl) This Control is used in a C# GUI Application. Also
used is a standard managed treeview. What i want di is, drag this Listitem
and drop it on the Treeview. Inside the Treeview Dropevent i want get the
Listitem as Object (not as text)
Of curse i need fill at DragStart the ETCFormat and StgMedium Structures
correct, but I have no Idea how. Text work fine. But this is not what i need.
I implementet all Interfaces (IdataObject, IDropTarget, IEtcEnumFormat etc)
How do i put the ListItem (pointer to my IListItem or CListItem) into
StgMedium ???
I dont think that i can do this via HGlobal? I Tryed this via Variant and
set VT_UNKNOWN to then Unk of my ListItem. No success. Who can help?