Missing data from XML data provider   

Hello
I have an ASP.net application that renders a report from a XML-file. The 
file looks like this.
<?xml version="1.0" standalone="yes"?>
<dsInstrumentList xmlns="http://localhost/XML/dsInstrumentList.xsd">
  <InstrumentList>
    <artnr>12317</artnr>
    <MIO-nummer>M306215</MIO-nummer>
    <Benämning>Termoelement</Benämning>
    <Fabrikat>Pentronic</Fabrikat>
    <Typbeteckning>Typ N</Typbeteckning>
    <Optioner />
    <Serienummer>08020497</Serienummer>
    <Id-nummer />
    <Status>Aktiv</Status>
    <Nästa_x0020_kalibrering />
    <Placering />
    <StatusId>10</StatusId>
    <Avdelning>MAA:Ludvika</Avdelning>
    <PÃ¥ServiceId>30</PÃ¥ServiceId>
    <Mätdonsansvarig>Herbert Breitfelder, MAL</Mätdonsansvarig>
    <MätdonsansvarigId>6</MätdonsansvarigId>
    <KalIntervall>12</KalIntervall>
    <Forvaltare>32</Forvaltare>
    <q_kal_ej>0</q_kal_ej>
    <Idnummer />
    <Företag_x0020_ort>Bodycote Metech AB, Ludvika</Företag_x0020_ort>
    <Senaste_x0020_kalibrering />
  </InstrumentList>
  <InstrumentList>
    <artnr>12317</artnr>
    <MIO-nummer>M306216</MIO-nummer>
    <Benämning>Termoelement</Benämning>
    <Fabrikat>Pentronic</Fabrikat>
    <Typbeteckning>Typ N</Typbeteckning>
    <Optioner />
    <Serienummer>08020498</Serienummer>
    <Id-nummer />
    <Status>Aktiv</Status>
    <Nästa_x0020_kalibrering />
    <Placering />

The file is created from a typed dataset using dataset.writeXml. With the 
report builder I have created a dataset that has a data source that points to 
the XML file (http://localhost/Test1.xml). I have no query in the dataset. 
The problem is that several columns (eg. Id-nummer) dissappears when I run 
the dataset. This problem only occurs when for example column "Id-nummer" is 
empty (<Id-nummer />) in the first row of the dataset (XML file) It works 
fine if "Id-nummer" has a value (<Id-nummer>25061</Id-nummer>)

Please advice!

date: Thu, 2 Oct 2008 06:45:00 -0700   author:   RobertS