Hi Quaritexa, sorry no there isn't any simple way set up to do it in v3. The methods for accessing the scene browser controls from script are new in v4.
<body class="SidePaneBody"
onload="var a = moi.ui.getUIPanel('moi://ui/BrowserPane.htm').document.querySelectorAll('#list div');
for (var i = 0; i < a.length; i++) a.item(i).style.display = 'block'">