Using Composer Birth and Death Dates

A fairly common way of presenting composer information in classical discographies is to include the composer's birth and death years. Here's an example from the Decca web site for a reasonably well-known composer:

Wolfgang Amadeus Mozart (1756 - 1791)

These dates can be entered in OCD in the composer profile ("Date born or formed" and "Date died or disbanded"). However, I cannot figure out to use them in an OCD display. I have created my own templates, so I know a bit about doing this, but I can't get composer birth & death data to display.

As far as I can tell, when I am working on the Album page tab in the template editor this information should be under Artist (OCD treats composers as artists) in the fields dateformed and datedisbanded. Yet when I try to use these fields I get nothing in the display, even though there is data entered for the composer. Here is what I have tried:

<dax:if(composer)>
<span class="navsep">&gt;</span> <dax:composerinfolink><dax:composer/> (<dax:dateformed/> - <dax:datedisbanded/>)
</dax:composerinfolink>
</dax:if>

This doesn't produce any date outcome (though the composer's name is properly displayed).
What should I be doing instead?