Hi. Finally I did release (now will publish into JED too). Action by click for placemarks - you can open Contact Details, Article Details and Placemark details (my placemark item view). I added plugin for K2 and module. Now you can active K2 overview map plugin and pass to K2 overview map module items from K2 - by post and ajax filters. In this case you configure K2 overview map plugin how get data from K2 items (and filter), and just publish K2 overview map module on place where you want to see map. I'll add some description in my documentation for this K2 integration.