As Shiraz Bhaiji answered, the metadata=res:///Model.csdl|res:///Model.ssdl|res://*/Model.msl was the case.
However I still had problems with constructing the proper string based on my Model localization, namespaces and assemby name. The very simple solution was to rename the .edmx file in Visual Studio(after than rename and get back to the original name), which triggered the automatic refreshing of the string in my Web.config
