Tempo markings not imported/exported correctly via MusicXML

MusicXML files created by MuseScore (r.1619) have a tempo tag set at "1" beats per minute. The score plays back very slowly when open in other MusicXML-compatible applications.

Here is the relevant section from a MusicXML file created by MuseScore:

      <direction placement="above">
        <direction-type>
          <words>. = 104</words>
          </direction-type>
        <sound tempo="1"/>
        </direction>

Here is the relevant section from a MusicXML file created by Finale 2007.

      <direction placement="above">
        <direction-type>
          <words default-y="40" font-family="Times New Roman" font-size="12" font-weight="bold">Moderato  </words>
        </direction-type>
        <direction-type>
          <metronome default-y="40" parentheses="yes">
            <beat-unit>quarter</beat-unit>
            <per-minute>c. 108</per-minute>
          </metronome>
        </direction-type>
        <sound tempo="108"/>
      </direction>