Comment 3 for bug 798673

Comment 2 isn't stated very clearly.

Each option that can be selected for units must have a DvCodedString bubble pasted onto the value element.

When the CCD (XML Schema) is created. These will then be created as a group/choice.

Example (w/o expanding all of the DvCodedString elements):

<xs:group name="unitsgroup">
<xs:choice>
   <DvcodedString1>
   <DvcodedString2>
   <DvcodedString3>
</xs:choice>
</xs:group>

Then in the DvQuantity units place it will reference the group: <xs:group ref="unitsgroup">

This forces the enduser to select one and only one option from the group.