Selector does not appear when dynamically creating object


So in an attempt to avoid the "You need a plugin" message, and do a dynamic tag build I have the following situation
An object is declared in the page header thus.
<object declare="declare" id="_xmlToken"></object>
On the click of the submit button add the required claims to the object tag using
var icObject = document.getElementById("_xmlToken");
// ... etc ...
AddObjectParameter(icObject, "requiredClaims", mandatoryClaims.toString());
where AddObjectParameter is taken from the HTML kit;
AddObjectParameter :function( element, name , value ) {
    var p = document.createElement('param');
    p.setAttribute('name' , name );
    p.setAttribute('value' , value );
and finally I set the mime type;
icObject.setAttribute( "type", "application/x-informationcard");
Now when I then attempt to get the value of the object the selector should appear; and indeed does in IE.
In Firefox, with the selector plugin, nothing happens. Firebug shows the object tag has the right format;
<object id="_xmlToken" declare="declare" type="application/x-informationcard">
<param name="requiredClaims" value="http://schemas.xmlsoap.org/ws/2005/05/identity/claims/privatepersonalidentifier "/>
Closed Mar 28, 2008 at 1:06 PM by ignisvulpis
Version 1.0.7 handles this.