[Vala] dbus question

[Zsombor <gzsombor gmail com>]

Hi !

I'm trying to call some dbus methods, but I'm confused with the syntax little bit. One of the dbus method returns an array of string, the other returns an array of string tuples, the dbus types are : 'as' and 'a(ss)'. How can I call this methods? If I wrote : 
  string[] result = object.SimpleQuery(....); 
Then valac throws the following error: 
 error: Assignment: Cannot convert from `string[]' to `string[]?'

And the same happens for the other method, where i've created a 'struct response  {   string key;  string value;}'. 

Am I missing something very obvious ? 

BR,
 Zsombor