[Remuless]

не совсем уверен в правильности решения, но сваял нечто подобное и оно работает, может кому пригодится:

var specorder = Xrm.Page.data.entity.attributes.get("new_specorder").getValue()[0].id;      
        var qso =
        "<fetch version='1.0' output-format='xml-platform' mapping='logical' distinct='false'>" +
          "<entity name='new_specorder'>" +
            "<attribute name='new_specorderid' />" +
            "<attribute name='new_scheme_description' />" +
            "<link-entity name='new_specorder' from='new_specorderid' to='new_specorderid' alias='ac'>" +
              "<filter type='and'>" +
                "<condition attribute='new_specorderid' operator='eq' uitype='new_specorder' value='" + specorder + "' />" +
                  "</filter>" +
                "</link-entity>" +
              "</entity>" +
            "</fetch>";
        //alert (qso);
        var rsorder = CrmServiceToolkit.Fetch(qso);
        //alert (rsorder);
        //-----------------------------------------------------------------------------------------------
        
        var text = rsorder[0].getValue("new_scheme_description");