XSLT Mapper doesn't support xsi:type

Question

I'm starting to think that XSLT Mapper supports only the basic features of XML Schema ...
It (XSLT Mapper in JDeveloper) does not seem to support mapping to generate this kind of element (cannot do it in Design view, when added to the Source view, cannot go back to Design view):
<HighLevel:ParentEntity xsi:type="HighLevel:AChildEntity" xmlns:HighLevel="someNamespace">
<A>ABC</A>
<B>1</B>
<FromAChildEntity>ABCDE</FromAChildEntity>
</HighLevel:ParentEntity>
If we leave this in Source view and run the xsl, the resulting XML has a validation error, the last element (FromAChildEntity is not known). The XML is valid in XML Spy.
This problem combines with not being able to map two source elements to one target element, makes XSLT Mapper not able to deal with XML Schema inheritance at all.... ?

Answer 1

I just want to reformat the XML from the original message (didn't realize I had to escape some of the characters). This is the XML that cannot be validated by JDeveloper):
<HighLevel:ParentEntity xsi:type="HighLevel:AChildEntity" xmlns:HighLevel="someNamespace">
&lt;A&gt;ABC&lt;/A&gt;
&lt;B&gt;1&lt;/B&gt;
<FromAChildEntity>ABCDE</FromAChildEntity>
</HighLevel:ParentEntity>