Buttons in first column do not scroll with table, z-index problems in IE7

I am putting a button in the column at index 0 of my data table. The column at index 1 is hidden using aoColumnDefs options. The table is loaded via ajax, then the buttons are initialized, then the data table is initialized. It looks fine in IE8 and FF, but when I use compatibility mode (IE7), the buttons do not scroll with the table body and they appear over the bottom toolbar of the datatable. I initialize the buttons just before the data table. Here's my code:

var initializeDataTable = function ($this, settings, $table) {

        $table.find("button.add").button({
                text: false,
                icons: {
                    primary: "ui-icon-plusthick"
                }
            }).click(function (event) {
                var $tr = $(this).parent().parent();
                // TODO: Implement add feature...
                return false;
            });


        settings.$recipeDataTable = $table.dataTable({
            "bJQueryUI": true
            , "sPaginationType": "full_numbers"
            , "sScrollY": "0px"
            , "aoColumnDefs": [
                {
                    "aTargets": [0]
                    , "bSearchable": false
                }
                ,{
                    "aTargets": [1]
                    , "bSearchable": false
                    , "bVisible": false
                }
                , {
                    "aTargets": [2, 5]
                    , "bSearchable": true
                    , "fnRender": function (obj) {

                        var html = "";
                        if (obj.aData[obj.iDataColumn].length > 18) {
                            html = "<span title='" + obj.aData[obj.iDataColumn] + "'>" + obj.aData[obj.iDataColumn].substring(0, 15) + "...</span>";
                        } else {
                            html = obj.aData[obj.iDataColumn];
                        }

                        return html;
                    }
                    , "bUseRendered": false
                }
            ]
            , "aaSorting": [[1, "asc"]]
        });

        settings.$pageCenter.resizeAll();
    };

How can i fix this? Thank you!

Robert