Using SQLXML Bulk Import with complicated schema - sql-server

Question

I'm trying to figure out how to use SQLXML bulk load for a rather complicated XML schema I have no control over (It's nominally a "standard"). A small example would be:
<RootElement>
<id root="e5404218-250a-4454-98d5-f9feee8a3589" />
<code code="93000" />
<time>
<low value="20140221095400.000" />
<high value="20140221095410.000" />
</time>
</RootElement>
With an AXSD schema of:
<?xml version="1.0"?>
<xs:schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:sql="urn:schemas-microsoft-com:mapping-schema">
<xs:element name="RootElement" sql:relation="re" >
<xs:complexType>
<xs:sequence>
<xs:element name="id" maxOccurs="1" minOccurs="1">
<xs:complexType>
<xs:attribute name="root" type="xs:ID" sql:field="id" sql:identity="useValue"/>
</xs:complexType>
</xs:element>
<xs:element name="code" minOccurs="1" maxOccurs="1">
<xs:complexType>
<xs:attribute name="code" type="xs:long"/>
</xs:complexType>
</xs:element>
<xs:element name="time" type="timeRange"/>
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:complexType name="timeRange">
<xs:choice>
<xs:sequence>
<xs:element name="low">
<xs:complexType>
<xs:attribute name="value" type="xs:string"/>
</xs:complexType>
</xs:element>
</xs:sequence>
<xs:sequence>
<xs:element name="high">
<xs:complexType>
<xs:attribute name="value" type="xs:string"/>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:choice>
</xs:complexType>
</xs:schema>
My sticking point seems to come from the ID being attached to an attribute on an element, instead of an element value, as no matter what tweaks I use, I get the error Schema: relationship expected on 'id'.. There really is no relationship there, it's just a container, since the committee that designed this schema seems to have really taken a liking to attributes.
All examples I find deal with the values being element content instead of attributes. This includes decorating the element with sql:is-constant (Constant element cannot have attributes), and various permutations of the sql:relation element.
The only option I could think of is to have a pre-processing step that makes attributes child elements, and base the schema on that, but that seems kind of hacky.
Any suggestions on how to convince SQLXML to do my bidding?