Clear Output Cashing on Sharepoint 2010
===

I'm trying to improve my site performance using output cache.
The problem is that the site is in 2 languages.
The site is a sharepoint site.
I use: 

    <%@ OutputCache Duration="1800" VaryByParam="None" %>

on the user control of my navigation visual web part.

On code behing when I switch language

     protected void ddlLanguages_SelectedIndexChanged(object sender, EventArgs e)
            {
                string selectedValue = ddlLanguages.SelectedValue.ToString();
                if (!String.IsNullOrEmpty(selectedValue))
                {
                    IISCommonFunctions.IISCurrentEnvironment.SetLanguage(selectedValue);
    
                    HttpResponse.RemoveOutputCacheItem("/_controltemplates/Services/NavigationWebPart.ascx");
                    Response.Redirect(Request.Path);
                    
                }
            }

But the problem here is that nothing happens. Nothing is cleared from cache.
Maybe the virtual path it's not right?

Please some help,

Thanks in advance

