Liferay friendly URL parameters lost

I'm using <ignored-parameter> tags in friendly-url-routes.xml to hide requets parameters. The Liferay documentation says "Ignored parameters do not effect URL recognition." When I redirect to a Struts action my parameters are lost and ignored.

Snippet from my friendly-url-routes.xml

<route>
    <pattern>/showSearch</pattern>
    <ignored-parameter name="searchId"/>
    <ignored-parameter name="pageNumber"/>
    <ignored-parameter name="count"/>
</route>

This is in struts.xml

<action name="showSearch" method="showSearch" class="com.mycomp.portlet.action.search.SearchAction">
        <result name="success">
            <param name="location">/WEB-INF/jsp/results/detail.jsp</param>
            <param name="searchId">${searchId}</param>
            <param name="pageNumber">${pageNumber}</param>
            <param name="count">${count}</param>
        </result>
</action>

How is it possible that the tag is affecting the functionality of the action when it is not supposed to? Is there anything I can do to hide these parameters but keep the functionality? I cannot use <generated-parameter> tags because these parameters do not always have a value

Thanks