function _initItemNavigation(){

		var oRootDomRef = this.getDomRef(),
			aDomRefs = this.$().find(".sapUiCalItem"),
			iColumns = this.getColumns();

		if (!this._oItemNavigation) {
			this._oItemNavigation = new ItemNavigation();
			this._oItemNavigation.attachEvent(ItemNavigation.Events.AfterFocus, this._handleAfterFocus, this);
			this._oItemNavigation.attachEvent(ItemNavigation.Events.FocusAgain, _handleFocusAgain, this);
			this._oItemNavigation.attachEvent(ItemNavigation.Events.BorderReached, _handleBorderReached, this);
			this.addDelegate(this._oItemNavigation);
			this._oItemNavigation.setHomeEndColumnMode(true, true);
			//this way we do not hijack the browser back/forward navigation
			this._oItemNavigation.setDisabledModifiers({
				sapnext: ["alt", "meta"],
				sapprevious: ["alt", "meta"],
				saphome : ["alt", "meta"],
				sapend : ["meta"]
			});
		}
		this._oItemNavigation.setRootDomRef(oRootDomRef);
		this._oItemNavigation.setItemDomRefs(aDomRefs);
		this._oItemNavigation.setCycling(false);
		this._oItemNavigation.setColumns(iColumns, true);
		var iIndex = this.getMonth() - this.getStartMonth();
		this._oItemNavigation.setFocusedIndex(iIndex);
		this._oItemNavigation.setPageSize(aDomRefs.length); // to make sure that pageup/down goes out of month

	}
Calculates the first and last displayed date about a given month.
@param {integer} iCurrentMonth the month about which the dates are calculated
@returns {object} two values - start and end date