Hi @Martin Staudigel you only can include DTD in the XSD if you define it using specific flags.

The solution is to create a new class to import the schema in XSD programatically. This is an example of the code:

Class XML.SchemaReader Extends %Persistent

{
ClassMethod ImportClasses(fileName As %String = "C:\Temp\example.xsd") As %Status
{
#include %occInclude
#include %occSAX
		#dim sReader as %XML.Utils.SchemaReader = ##class(%XML.Utils.SchemaReader).%New()
		#dim features as Filero.DataType.String
		set sReader.SAXFlags = $$$SAXFULLDEFAULT-$$$SAXVALIDATIONREUSEGRAMMAR
		set sReader.MakePersistent = 0
		set sReader.MakeRelationships = 0
		set sReader.GenerateXMLNILNOOBJECT = 1
		set sReader.GenerateXMLNIL = 1
		set sReader.KeepEmptyClasses = 1
		set features("BINARYASSTREAM") = 1
		quit sReader.Process(fileName,"ImportedScheme",.features)
}
}

ObjectScript
ObjectScript

This code will create a package "ImportedScheme" in your IRIS