Define name which we can import looks like this:

<definedName name="Test">Sheet1!$A$1</definedName>

The case which can not be handled by RadSpreadProcessing looks like this:

<definedName name="Test"><![CDATA[Sheet1!$A$1]]></definedName>

The CDATA element is used to escape the inner text in order not to be parsed as XML. That means this is а valid case, and RadSpreadProcessing should handle it.