ColVis with jquery cookie?

Been trying to set up a cookie for saving and returning the ColVis data. My basic code is (hand typed from intranet):

var columnDisplayIndex = $.cookie("columnIndexCookie");
$("#datatable).ready(function(){
    $("#datatable).dataTable({
     ......
     "aoColumnDefs" : [{
               "bVisible" : false, "aTargets" : [columnDisplayIndex]
     }]
     .......
     "fnDrawCallback" :
          function(oSettings){
                   var vCols = new Array();
                   .each($("#openTable").dataTable().fnSettings().aoColumns, function(c){
                           if(oSettings.aoColumns[c].bVisible == false){
                                  vCols.push(c);
                            }
                    });
                    $.cookie("columnIndexCookie", vCols, {expires:90})
        .....

I can return the values (print out in the firebug console logs) when I click the ColVis buttons and I can see the values in the cookie. I can return the values from the var in the cookie (var columnDisplayIndex ) but it doesn't seem to read it on refresh or load when it gets to the aoColumnDefs.

Any ideas what i'm missing here?