Is it legal to embed xml within an <annotation><documentation>

My question is "Is my schema wrong? or, is the schema quality checker 
wrong?"

I'm developing a schema for XSL:FO. In my schema I've included a bunch 
of <annotation><documentation> elements for various purposes. IBM's 
schema quality checker complains if I include certain xml elements 
within the annotation. Here's an example where it complains about the 
element <length/>

<simpleType name = "length_range_Type">
    <annotation>
        <documentation>
            A compound datatype, with components: minimum, optimum, 
maximum. Each component is a <length/>. If "minimum" is greater than 
optimum, it will be treated as if it had been set to "optimum". If 
"maximum" is less than optimum, it will be treated as if it had been set 
to "optimum". A property may define additional constraints on the values.
        </documentation>
    </annotation>
    <xs:restriction>
        <xs:simpleType>
            <xs:list>
                <xs:simpleType>
                    <xs:restriction base = "fo:length_Type"/>
                </xs:simpleType>
            </xs:list>
        </xs:simpleType>
        <xs:minLength value = "3" />
        <xs:maxLength value = "3" />
    </xs:restriction>
</simpleType>

Initializing Schema Quality Checker. Please wait ...
SchemaQualityChecker has been initialized
PROCESSING \fop-0.20.1\fop4f.xsd time : 2002-06-12T11:21:58 ...
\fop-0.20.1\fop4f.xsd (file 1 of 1) now being read ...
------------------------------------------------------------------------
ERROR
 file = file:C:/Fop-0.20.1/fop4f.xsd line 948 column 14
SEVERITY: 1
ERROR TYPE: 1
MESSAGE
cvc-complex-type.4: Attribute 'value' must appear on element 'length'.

Received on Wednesday, 12 June 2002 14:36:02 UTC