Inserting attributes from one instance to another

I've been using the firefox extntion for a while  and you used to be able to
insert attributes from one instance to another using the following syntax:
 <xforms:trigger appearance="minimal" ref="self::node()[not(@type)]">
    <xforms:label>Add type</xforms:label>
     <xforms:insert ev:event="DOMActivate"
context="instance('metadata')//mods:mods/
mods:titleInfo[index('titleInfo')]"
           origin="instance('template')/mods:titleInfo/@type"/>
</xforms:trigger>


This does not appear to work anymore, is my syntax wrong, or is this no
longer supported?

Thanks.

-Winona