SLD: Label-entry lacks PropertyName-tag

[sholl]

When exporting a mapfile to SLD the Label-tags inside the SLD lacks the ogc:PropertyName-tag:

<Rule>
  <Name>Druckleitung</Name>
  <Filter>
    <PropertyIsEqualTo>
      <PropertyName>TYP</PropertyName>
      <Literal>d</Literal>
    </PropertyIsEqualTo>
  </Filter>
  <LineSymbolizer>
    <Stroke>
      <CssParameter name="stroke">#ffff00</CssParameter>
      <CssParameter name="stroke-width">3</CssParameter>
    </Stroke>
  </LineSymbolizer>
  <TextSymbolizer>
    <Label>BETREIBERTYP</Label>
    <Font>
      <CssParameter name="font-family">arial</CssParameter>
      <CssParameter name="font-size">7</CssParameter>
    </Font>
    <LabelPlacement>
      <PointPlacement>
        <AnchorPoint>
          <AnchorPointX>0.5</AnchorPointX>
          <AnchorPointY>0.5</AnchorPointY>
        </AnchorPoint>
      </PointPlacement>
    </LabelPlacement>
    <Fill>
      <CssParameter name="fill">#000000</CssParameter>
    </Fill>
  </TextSymbolizer>
</Rule>

The TextSymbolizer should look like this in order to print the values of the attribute column 'BETREIBERTYP' instead of the term 'BETREIBERTYP'.

<TextSymbolizer>
    <Label>
      <ogc:PropertyName>BETREIBERTYP</ogc:PropertyName>
    </Label>
    <Font>
...

[jmckenna]

I am hitting this same bug as part of the FOSS4G WMS benchmarking exercise, where I am trying to share my SLDs with other server teams - I am generating an SLD with phpmapscript's generateSLD() function, but the exercise teams are reporting that it is an invalid SLD, because of this missing <ogc:PropertyName> tag.