Is it possible to hide or manipulate the jqGrid "sort" icons?

I have a custom, multi-column sort attached to my jqGrid instance by means of the onSortCol event:

onSortCol: function(index, iCol, sortorder) {
    //Manipulate the sort order via custom code, and store it in postData.

    return 'stop';
}

The problem I'm running into is that the sort icons in the column headers are falling out of synch 开发者_高级运维with the actual sorting, because their behavior is slightly different from what I'm trying to implement.

I've tried using setParam('sortname'...), but that specifically doesn't change the sort icon. I've also tried sortGrid, but that raises the onSortCol event in a way that seems to be indistinguishable from a user's click.

If hiding via CSS is the only option, what's the most effective selector to target ONLY the sort headers in a specific grid?

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I am currently using the following CSS:

#gbox_MyGrid .s-ico span {
    display:none;
}

For a grid with an ID of MyGrid.

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I disable the sort for a particular column with 'sortable: false,' like below:

{ name:'ColumnName', index:'ColumnName', width: 80, sortable: false, align:'center'}

Good luck.