jQuery Grid Plugin - jqGrid

Hi.  I need to center some of my column headers, but the align property doesn't seem to be working for me.  Here's the general setup of my code:

var columnNames = ['Product<br />Group','<br />Description','On Hand<br />Weight','% of<br />Total','Per Lb<br />Cost','Avg Monthly<br />Sales Wgt','Months<br />Supply','Turnover<br />Rate'];
var columnModel = [
                {name:'id', resizable:false, index:'id', width:40, align:'center'},
                {name:'description', resizable:false, index:'desc', width:90, align:'left', sortable:false},
                {name:'ohWeight', resizable:false, index:'ohWeight', align:'center', width:55},
                {name:'pctOfTotal', resizable:false, index:'pctOfTotal', align:'center', width:37},
                {name:'perLbCost', resizable:false, index:'perLbCost', width:43, align:'center'},
                {name:'avgMWgt', resizable:false, index:'avgMWgt', width:71, align:'center'},
                {name:'monthsSupply', resizable:false, index:'monthsSupply', width:50, align:'center'},
                {name:'turnoverRate', resizable:false, index:'turnoverRate', width:50, align:'center'}];
               

            $("#results").jqGrid(
            {
                colNames: columnNames, 
                colModel: columnModel,  ...

Would the fact that I'm entering variables for colNames and colModel make a difference?  Can you guys see if I'm missing anything?