Jaxb behaviour is odd - jaxb

Question

I am trying to marshall and unmarshal gpx files with an extension. The gpx schema allows to have extension added in the extensions tag example:
<trkpt lat="51.219983" lon="6.765224">
<ele>52.048584</ele>
<time>2009-06-19T10:13:04Z</time>
<extensions>
<gpxdata:hr>164</gpxdata:hr>
<gpxdata:cadence>99</gpxdata:cadence>
</extensions>
</trkpt>
The GPX file is correct and passes unmarshalling like this:
JAXBContext jaxbContext = JAXBContext.newInstance(GpxType.class, com.cluetrust.xml.gpxdata._1._0.ObjectFactory.class);
Unmarshaller unmarshaller = jaxbContext.createUnmarshaller();
File file = new File("src/test/resources/gpx-example.gpx");
JAXBElement<GpxType> unmarshal = (JAXBElement<GpxType>) unmarshaller.unmarshal(file);
GpxType gpx = unmarshal.getValue();
Two things for me are odd. First off all I have to unmarshal to a JAXBElement and cannot go straight to GpxType, I have to go to the JAXBElement first.
Second of all and that is (for me the biggest problem) once I have the GpxType object. Part is indeed done, but the extensions are not:
ExtensionsType extensions = gpx.getExtensions();
List<Object> extensionsAny = extensions.getAny();
for (Object object : extensionsAny){
System.out.println(object.getClass());
if (object instanceof JAXBElement) {
JAXBElement element = (JAXBElement) object;
LapType lapType = (LapType) element.getValue();
System.out.println(lapType.getStartTime());
}
It seems I have to jump through some hoops here. I have setup a very small project on github where this is shown jaxbproblem. The complete example GPX file i am using is there too. The namespaces in it are correct:
<gpx xmlns="http://www.topografix.com/GPX/1/1"
xmlns:gpxdata="http://www.cluetrust.com/XML/GPXDATA/1/0"
creator="pytrainer http://sourceforge.net/projects/pytrainer" version="1.1">
EDIT:
Relevant part in the schema is :
<xsd:element name="lap" type="lapType">
<xsd:annotation>
<xsd:documentation>
Lap is used to contain information about an individual lap of activity.
Depending upon the device, this may contain a variety of additional information.
Depending upon the device, this may be contained within a run or course.
</xsd:documentation>
</xsd:annotation>
</xsd:element>
and:
<xsd:complexType name="lapType">
<xsd:sequence>
<xsd:element name="index" type="xsd:int" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>The index of the lap in the internal list.</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="startPoint" type="locationType" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>The starting point of the lap in Lat/Long</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="endPoint" type="locationType" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>The ending point of the lap in Lat/Long</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="startTime" type="xsd:dateTime" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>The starting time of the lap</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="elapsedTime" type="xsd:float" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>The total elapsed time of the lap in seconds</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="calories" type="xsd:nonNegativeInteger" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>The number of calories burned during the lap</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="distance" type="xsd:float" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>Distance (in m) covered during the lap</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="trackReference" type="trackReferenceType" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>Reference information for the track which corresponds to this lap</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="summary" type="summaryType" minOccurs="0" maxOccurs="unbounded">
<xsd:annotation><xsd:documentation>Performance summary elements summarizing different performance measurements, such as cadence, hr, etc.</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="trigger" type="triggerType" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>The trigger of the lap. On some devices, the lap may be manual or automatic based on attributes known by the device.</xsd:documentation></xsd:annotation>
</xsd:element>
<xsd:element name="intensity" type="intensityKind" minOccurs="0" maxOccurs="1">
<xsd:annotation><xsd:documentation>The intensity of the lap (whether resting or active)</xsd:documentation></xsd:annotation>
</xsd:element>
</xsd:sequence>
</xsd:complexType>
This is just one of the many types that are being introduced with this schema that can be found here
What am I doing wrong?