salve a tutti,
ho dichiarata la seguente struttura in xsd :
codice:
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">	
	<xsd:include schemaLocation="opencms://opencms-xmlcontent.xsd"/>
<xsd:element name="Primo_piano_Attachment" type="OpenCmsPrimo_piano_Attachment"/>

	<xsd:complexType name="OpenCmsPrimo_piano_Attachment">
		<xsd:sequence>
			<xsd:element name="Attachment" type="OpenCmsAttachment" minOccurs="0" maxOccurs="unbounded"/>
		</xsd:sequence>
	</xsd:complexType>

	<xsd:complexType name="OpenCmsAttachment">
		<xsd:choice>
			<xsd:element name="Add" type="OpenCmsString" minOccurs="1" maxOccurs="1" />
            		<xsd:element name="File" type="OpenCmsVfsFile" minOccurs="1" maxOccurs="1" />
			<xsd:element name="Link" type="OpenCmsString" minOccurs="1" maxOccurs="1" />
			<xsd:element name="Image" type="OpenCmsVfsFile" minOccurs="1" maxOccurs="1" />
                </xsd:choice>
           <xsd:attribute name="language" type="OpenCmsLocale" use="optional"/>
        </xsd:complexType>

	
		
			     
</xsd:schema>
Premetto che uso opencms e al momento della creazione di un xml mi da' il seguente errore :

ErrorInvalid OpenCms content definition XML schema structure:
Element "/xsd:schema/xsd:complexType[2]/xsd:choice" must be "xsd:sequence", not "xsd:choice".

cosa potrebbe significare??
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