Tinymce shortcut to add custom styles

In my tinymce initialization I use a pre-defined style

style_formats : [ 
    {title : 'Date', inline : 'span', classes : 'date'},
    {title : 'Trend UP', inline : 'span', classes : 'trend_up'},
    {title : 'Trend DOWN', inline : 'span', classes : 'trend_down'},
    {title : 'Trend NO', inline : 'span', classes : 'trend_no'}
]

This pre-defined style wraps the selected content into a span tag and adds a specific class to it; but now I need to add shortcuts (hotkeys) that will provide the same functionality

For this I have created plugin in which my hotkey will be defined

(function(){

    tinymce.create('tinymce.plugins.MyShortcuts', {
        init : function(ed, url) {
            ed.addShortcut('ctrl+e','Format Blockquote', ['FormatBlock', false, 'blockquote'], this);
        }
    });

    // Register plugin with a short name
    tinymce.PluginManager.add('my_shortcuts', tinymce.plugins.MyShortcuts);
})();

And it works great with blockquote. But I didn't find any useful information in tinymce documentation to implement shortcuts for my custom styles .

Can someone help me how to implement this functionality? i try to do

ed.addShortcut('ctrl+e','Format Trend UP', ['FormatBlock', false, 'Trend UP'], this);

and

ed.addShortcut('ctrl+e','Format Trend UP', ['StylesBlock', false, 'Trend UP'], this);

But it doesn't work.