Xamarin Forms adding Service Reference to PCL - no XmlElement in System.Xml error

Hi there,

I've created new Xamarin Forms Project (with PCL library). Now I would like to integrate it with my web service - so I added Service Reference to it in VS 2013:

1. Simply add Service Reference, enter Address to my service, click OK.
2. Then I am trying to compile my project and got errors connected to System.Xml reference missing...

That's error:

Error 25 The type or namespace name 'XmlElement' does not exist in the namespace 'System.Xml' (are you missing an assembly reference?) F:\Xamarin\MyProjects\Service References\MyService\Reference.cs

Is it possible to add service ref to my web service based on xml in PCL? Or what I should use alternatively?