sorry but you probably are not going to be able to use the editor in databinding scenarios like in FormView
If you look at any feature where the editor is used we have to call SiteUtils.SetupEditor(edContent);
in oninit event, but that is not likely to work in data binding scenarios.
you "might" be able to use the <HTMLEditor:Editor id="foo" runat="server" />
Hope it helps,
Joe