R help - Mar 2010 - Reading a SpreadsheetML / XMLNS into R xmlns="urn:schemas-microsoft-com:office:spreadsheet

Hello,
I use a software that outputs the data in a form/dialect(?) of xml (I
think its called "SpreadsheetML", see below for an excerpt). It allows
(admittedly) easy import of such files into Excel. I would like,
however, to import it directly into R. I am familiar how to do that
with standard xml-files (mostly thanks to Duncan Temple Lang's help).
But I haven't found the right command yet to do it with this kind of
data in R. I would figure it couldn't be to difficult as it is
designed to hold the data in separate sheets that contain a single
table.

Any hint appreciated.
Have a great weekend!
Best,
Stefan

<?xml version="1.0"?>
<?mso-application progid="Excel.Sheet"?>
<Workbook xmlns="urn:schemas-microsoft-com:office:spreadsheet"
 xmlns:o="urn:schemas-microsoft-com:office:office"
 xmlns:x="urn:schemas-microsoft-com:office:excel"
 xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet"
 xmlns:html="http://www.w3.org/TR/REC-html40">
 <DocumentProperties
xmlns="urn:schemas-microsoft-com:office:office">
  <Version>12.00</Version>
 </DocumentProperties>
 <ExcelWorkbook xmlns="urn:schemas-microsoft-com:office:excel">
  <WindowHeight>10005</WindowHeight>
  <WindowWidth>10005</WindowWidth>
  <WindowTopX>120</WindowTopX>
  <WindowTopY>135</WindowTopY>
  <ProtectStructure>False</ProtectStructure>
  <ProtectWindows>False</ProtectWindows>
 </ExcelWorkbook>
 <Styles>
  <Style ss:ID="Default" ss:Name="Normal">
   <Alignment ss:Vertical="Bottom"/>
   <Borders/>
   <Font ss:FontName="Calibri" x:Family="Swiss"
ss:Size="11"
ss:Color="#000000"/>
   <Interior/>
   <NumberFormat/>
   <Protection/>
  </Style>
 </Styles>


 <Worksheet ss:Name="age 0in 2010">
  <Table ss:ExpandedColumnCount="12"
ss:ExpandedRowCount="526" x:FullColumns="1"
   x:FullRows="1" ss:DefaultRowHeight="15">
   <Row>

[... omission...]

 </Table>
  <WorksheetOptions
xmlns="urn:schemas-microsoft-com:office:excel">
   <ProtectObjects>False</ProtectObjects>
   <ProtectScenarios>False</ProtectScenarios>
  </WorksheetOptions>
 </Worksheet>
</Workbook>