Reading XML tag with namespace (IE8)

This code is working on all major browsers but IE8 doesn´t support getElementsByTagNameNS. Anybody know how to read a xml tag with a namespace in IE8 (i.e. content:encoded) using this code?

var properties = new Array("title", "link", "description", "encoded");
    var tmpElement = null;

    for (var i=0; i<properties.length; i++)
    {
        if(itemxml.getElementsByTagNameNS){

         tmpElement = itemxml.getElementsByTagNameNS("*", properties[i])[0];

        }else{

        //???????????????????????
        }

        if (tmpElement != null){
            eval("this."+properties[i]+"=tmpElement.childNodes[0].nodeValue");

    }

    }