I omited irrelevant information but each xs:element is a complex type
<xs:element name="ICMS">
	<xs:complexType>
		<xs:choice>
			<xs:element name="ICMS00" />
			<xs:element name="ICMS10" />
			<xs:element name="ICMS20" />
			<xs:element name="ICMS30" />
			<xs:element name="ICMS40" />
			<xs:element name="ICMS51" />
			<xs:element name="ICMS60" />
			<xs:element name="ICMS70" />
			<xs:element name="ICMS90" />
			<xs:element name="ICMSPart" />
			<xs:element name="ICMSST" />
			<xs:element name="ICMSSN101" />
			<xs:element name="ICMSSN102" />
			<xs:element name="ICMSSN201" />
			<xs:element name="ICMSSN202" />
			<xs:element name="ICMSSN500" />
			<xs:element name="ICMSSN900" />
		</xs:choice>
	</xs:complexType>
</xs:element>