Checkboxes with values from a dictionary

gistfile1.xml

<xh:html xmlns:xh="http://www.w3.org/1999/xhtml"
      xmlns:xf="http://www.w3.org/2002/xforms"
      xmlns:xxf="http://orbeon.org/oxf/xml/xforms"
      xmlns:ev="http://www.w3.org/2001/xml-events"
      xmlns:xs="http://www.w3.org/2001/XMLSchema"
      xmlns:fr="http://orbeon.org/oxf/xml/form-runner">
    <xh:head>
        <xf:model>
            <xf:instance id="data">
                <data/>
            </xf:instance>
            <xf:instance id="items">
                <items>
                  <item>
                    <id>1</id>
                    <name>One</name>
                  </item>
                  <item>
                    <id>2</id>
                    <name>Two</name>
                  </item>
                </items>
            </xf:instance>
        </xf:model>
    </xh:head>
    <xh:body>
        <xf:select appearance="full" ref=".">
            <xf:itemset ref="instance('items')/item">
                <xf:label ref="name"/>
                <xf:value ref="id"/>
            </xf:itemset>
        </xf:select>
    </xh:body>
</xh:html>