This feature is not available in current version. The code below shows a simple way to display the rotated title when the west panel is collapsed.
$(function(){
var p = $('body').layout('panel','west').panel({
onCollapse:function(){
var title = $('body').layout('panel','west').panel('options').title; // get the west panel title
var p = $('body').data('layout').panels['expandWest']; // the west expand panel
p.html('<div style="-moz-transform: rotate(90deg);padding:6px 2px">'+title+'</div>');
}
});
});