PostItem to 'read' MailItem

I'm trying the workaround to save a 'read' MailItem as suggested by
Dmitry and others as follows:

_PostItemPtr	NewPostItem;
NewPostItem = m_Explorer->Application->CreateItem(olPostItem);

NewPostItem->Attachments->Add(NewFileName, olByValue, 1, NewFileName);
// Some additional changes

NewPostItem->MessageClass = _T("IPM.Note");
NewPostItem->Save();

_bstr_t ThisEntryId = NewPostItem->EntryID;
NewPostItem->Close(olSave);

MapiNameSpace	= m_Explorer->Application->GetNamespace(L"MAPI");
_MailItemPtr	NewMailItem	= MapiNameSpace->GetItemFromID(ThisEntryId);
NewMailItem->Display();

However the NewMailItem object is always null.  Any ideas why, or
better yet, how to fix this?

Thanks, J