Explicitly go to a given view in an action seam doesn't work

[roccapl_]

this question is related to my previous question http://answers.nuxeo.com/questions/4209/bind-a-content-view-definition-to-a-particular-action-seam but since it's a slightly different situation I'll post another one:

I've created a fresh Action Seam using the wizard in Nuxeo Ide and I noticed in the source comments this lines inside the doGet method:

// If you want to explicitly go to a given view
    // just return the outcome string associated to the view
    //
    // return "someView";

so I replaced the default return null with return "my_cool_view" inside the method

then I created a contribution to a Content View defined like this:

<component name="com.example.FilterView">
<extension target="org.nuxeo.ecm.platform.ui.web.ContentViewService"
	point="contentViews">
	<contentView name="my_cool_view">
		<coreQueryPageProvider>
			<property name="coreSession">#{documentManager}</property>
			<pattern>
				SELECT * FROM Document WHERE
				dc:title = 'test'
			</pattern>
			<parameter>#{currentDocument.id}</parameter>
			<sort column="dc:title" ascending="true" />
			<pageSize>20</pageSize>
		</coreQueryPageProvider>
		<cacheKey>#{currentDocument.id}</cacheKey>
		<cacheSize>10</cacheSize>
		<refresh>
			<event>documentChanged</event>
			<event>documentChildrenChanged</event>
		</refresh>
		<resultLayouts>
			<layout name="document_listing_ajax" title="document_listing"
				translateTitle="true" iconPath="/icons/document_listing_icon.png"
				showCSVExport="true" showPDFExport="true" showSyndicationLinks="true" />
			<layout name="document_listing_ajax_compact_2_columns" title="document_listing_compact_2_columns"
				translateTitle="true" iconPath="/icons/document_listing_compact_2_columns_icon.png" />
			<layout name="document_listing_ajax_icon_2_columns" title="document_listing_icon_2_columns"
				translateTitle="true" iconPath="/icons/document_listing_icon_2_columns_icon.png" />
		</resultLayouts>
		<selectionList>CURRENT_SELECTION</selectionList>
		<actions category="CURRENT_SELECTION_LIST" />
	</contentView>
</extension></component>

but when I click the button of the action seam this doesn't show the other view.

What have I done wrong?