At the moment my Liferay server (Liferay 7.0) only generates ETAG Values for some pages (layout).
For pages that only contain the web content display portlet, the ETAG Value are generated. But no ETAG Value is generated for pages with the asset publisher or with some portlets developed in-house.
How can you get Liferay to generate ETAG Values for pages containing the asset publisher or for pages containing our selfdeveloped portlets?

• Is it possible  over the configuration?
• Or do we have to implement our own filter for that matter?

Here ist the current relevant part of our portal-ext.properties file: 
com.liferay.portal.servlet.filters.layoutcache.LayoutCacheFilter=true