function GetStringFromClipboard: WideString;
var  Data: THandle;
begin
if not IsClipboardFormatAvailable(CF_UNICODETEXT) then
Result := Clipboard.AsText
else begin
Clipboard.Open;
Clipboard.SetAsHandle(CF_UNICODETEXT, Data);
try
if Data <> 0 then
Result := PWideChar(GlobalLock(Data))
else
Result := '';
finally
if Data <> 0 then
GlobalUnlock(Data);
Clipboard.Close;
end;
end;
end;

Range := (editor.selection.createRange as IHTMLTxtRange);  
range.execCommand('Paste', false, getstringfromclipboard);