Editing RSS standard widget from Aptana

I am completely new to programming widsets and don't have too much experience with java.
I downloaded Aptana Studio and used the wizard to create a standard rss reader functionality.
Before I load the rss reader I have a standard html page.
WHen I load the actual reader I want to have a go back functionality, either in the menu (preferred) or in the soft keys.
Here is the part of the code that I changed ([U]in underlined[/U]), the Back button does show in the Menu but how to integrate the go back functionality?

[CODE]

// Constants for menu item identifiers.
var MENU_ITEM_SETTINGS = 0;
var MENU_ITEM_REFRESH = 1;
var MENU_ITEM_ABOUT = 2;
[U]var MENU_ITEM_BACK = 3;[/U]

// Feed update timer identifier.
var updateTimerId = null;

//About menu lable
var aboutLabel;

// Feed name, URL and update frequency (in milliseconds; -1 if no auto update).
var feedName = "N95 News";
var feedURL = "http://feeds.feedburner.com/N95";
var feedUpdateFrequency = -1;

// Next scheduled update time; -1 if never.
var feedUpdateTime = -1;

// Called from the onload event handler to initialize the widget.
function init() {
if (window.widget) {
// set tab-navigation mode and show softkeys
widget.setNavigationEnabled(false);
window.menu.showSoftkeys();

// create menu
var settingsMenuItem = new MenuItem("Settings", MENU_ITEM_SETTINGS);
settingsMenuItem.onSelect = menuItemSelected;
menu.append(settingsMenuItem);
var refreshMenuItem = new MenuItem("Refresh", MENU_ITEM_REFRESH);
refreshMenuItem.onSelect = menuItemSelected;
menu.append(refreshMenuItem);
var aboutMenuItem = new MenuItem("About", MENU_ITEM_ABOUT);
aboutMenuItem.onSelect = menuItemSelected;
menu.append(aboutMenuItem);
[B][U][B]var backMenuItem = new MenuItem("Back", MENU_ITEM_BACK);
backMenuItem.onSelect = menuItemSelected;
menu.append(backMenuItem);[/B][/U][/B]
}



// Callback for when menu items are selected.
function menuItemSelected(id) {
switch (id) {
case MENU_ITEM_SETTINGS:
showSettings();
break;
case MENU_ITEM_REFRESH:
updateFeed();
break;
case MENU_ITEM_ABOUT:
showAboutView();
break;
[U]case MENU_ITEM_BACK:
showGoBack();
break;[/U]
}
}

[I]Function for go back??? :confused:[/I]

[/CODE]