Another Schema Question

I am trying to define a schema for Latitide/Longitude such that it can be
expressed as degrees, minutes, and seconds.

Normally, the restrictions would be (for latitude) degrees > 90, minutes >
60, and seconds > 60

The problem is that 90d0m0s is also a valid latitude.

My colleague who swears by XML Spy (while I just swear at it) came up with this:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
   <xs:complexType name="LatitudeType">
      <xs:choice>
         <xs:sequence>
            <xs:element name="deg">
               <xs:simpleType>
                  <xs:restriction base="xs:decimal">
                     <xs:maxInclusive value="90"/>
                  </xs:restriction>
               </xs:simpleType>
            </xs:element>
            <xs:element name="min" type="xs:decimal" fixed="0"/>
            <xs:element name="sec" type="xs:decimal" fixed="0"/>
            <xs:element name="dir">
               <xs:simpleType>
                  <xs:restriction base="xs:string">
                     <xs:enumeration value="N"/>
                     <xs:enumeration value="n"/>
                     <xs:enumeration value="S"/>
                     <xs:enumeration value="s"/>
                  </xs:restriction>
               </xs:simpleType>
            </xs:element>
         </xs:sequence>
         <xs:sequence>
            <xs:element name="deg">
               <xs:simpleType>
                  <xs:restriction base="xs:decimal">
                     <xs:minInclusive value="0"/>
                     <xs:maxExclusive value="90"/>
                  </xs:restriction>
               </xs:simpleType>
            </xs:element>
            <xs:element name="min">
               <xs:simpleType>
                  <xs:restriction base="xs:decimal">
                     <xs:minInclusive value="0"/>
                     <xs:maxExclusive value="60"/>
                  </xs:restriction>
               </xs:simpleType>
            </xs:element>
            <xs:element name="sec" fixed="0">
               <xs:simpleType>
                  <xs:restriction base="xs:decimal">
                     <xs:minInclusive value="0"/>
                     <xs:maxExclusive value="60"/>
                  </xs:restriction>
               </xs:simpleType>
            </xs:element>
            <xs:element name="dir">
               <xs:simpleType>
                  <xs:restriction base="xs:string">
                     <xs:enumeration value="N"/>
                     <xs:enumeration value="n"/>
                     <xs:enumeration value="S"/>
                     <xs:enumeration value="s"/>
                  </xs:restriction>
               </xs:simpleType>
            </xs:element>
         </xs:sequence>
      </xs:choice>
   </xs:complexType>
</xs:schema>

Oxygen, the editor I use,  says it is invalid.

E cos-element-consistent: Error for type 'LatitudeType'. Multiple elements
with name 'deg', with different types, appear in the model group.
E cos-nonambig: "":deg and "":deg (or elements from their substitution
group) violate "Unique Particle Attribution". During validation against
this schema, ambiguity would be created for those two particles.


Is there a valid way to to this ?