jQuery Grid Plugin - jqGrid

Hi,

First, thank you for this wonderfull component.

Now I have a question: How do I remove custom buttons from the navigator (the pager)?

I add them like this:

$("#org_tree").jqGrid({
    ...
})
.jqGrid("navGrid","#tree_pager",{edit:false,add:false,del:false,search:false,refresh:false})
.jqGrid("navButtonAdd","#tree_pager",{
        onClickButton:switchTree,caption:"Show Full Tree"
    }
);

Now this is my function switchTree:

function switchTree(){
    $("#org_tree")
        .setGridParam({url:"../dev/org1.json",page:1})
        .trigger("reloadGrid")
        .jqGrid("navButtonAdd","#tree_pager",{
                onClickButton:switchTree2,caption:"Show My Tree"
            });
}

This function adds the button, so I have 2 buttons , now how can I replace the button "show full tree" with the button "show my tree"?

thanks in advance.