COM and Editor: openDocument with XML Schema?

Hi,

I'm trying to open documents via COM in Arbortext Editor and supply Doctype and Stylesheet on the fly. This works fine for DTDs, but when I specifiy an XML Schema instead, the Editor fails to open the document. Do I miss something or is this simply not possbile with the Editor?

Call:

openDocument(pathToFile, 0x0040|0x0100, "", "", pathToXsdFile, pathToStylesheetFile);

Error:

Source: Epic.Application.1

Description: [A30295] Application.openDocument: Fehler beim Öffnen (something like "Error while opening")

Parser-Message:

pathToXsdFile : Line: 2 Column: 3
Expected a markup declaration

Line 2 of the XSD contains the following:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

Best regards,

Mathias