WP8: Setting up SampleData

Question

i want to create sample data in form of a List for my LongListSelector in wp8 but cannot get it to work. Can you help?

ListEntryModel.cs:

    [...]
    namespace LongListSelectorStudies.ViewModels
    {
        public class ListEntryModel
        {
            public string Text { get; set;}
            public List<string> Liste { get; set; }
        }
    }

SampleData.xaml:

   <vm:ListEntryModel 
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:vm="clr-namespace:LongListSelectorStudies.ViewModels"

      xmlns:sys="clr-namespace:System;assembly=mscorlib"

      Text="Test">

        <vm:ListEntryModel.Liste>
            <sys:String>One</sys:String>
            <sys:String>Two</sys:String>        
        </vm:ListEntryModel.Liste>

    </vm:ListEntryModel> 

Error: The element "Liste" could not be identified or the element is not accessible. I am not using the english version of Visual Studio thus the error message may not be accurate. Thank you for your help!