how to load custom staticresource

I have to 2 files: ButtonStyle.xaml and Constants.xaml

in App.xaml, i will init

    <Application.Resources>        
            <ResourceDictionary>
                <ResourceDictionary.MergedDictionaries>
                    <ResourceDictionary Source="/Zalo;component/ResourceDictionary/480x800/ConstantsStyle.xaml"/>
                    <ResourceDictionary Source="/Zalo;component/ResourceDictionary/480x800/ButtonStyle.xaml"/>
                 </ResourceDictionary.MergedDictionaries>
            </ResourceDictionary>
......
    </Application.Resources>

file Constants.xaml

<ResourceDictionary
    xmlns="http://ift.tt/o66D3f"
    xmlns:x="http://ift.tt/mPTqtT"    
    xmlns:vsm="clr-namespace:System.Windows;assembly=System.Windows">

    <Thickness x:Key="GenericButtonStylePadding">0,7</Thickness>

</ResourceDictionary>

file ButtonStyle.xaml

<ResourceDictionary
    xmlns="http://ift.tt/o66D3f"
    xmlns:x="http://ift.tt/mPTqtT"
    xmlns:vsm="clr-namespace:System.Windows;assembly=System.Windows"
    xmlns:toolkit="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls.Toolkit" 
    xmlns:usercontrols="clr-namespace:Zalo.UserControls">

    <Style x:Key="GenericButtonStyle" TargetType="Button">
        <Setter Property="VerticalContentAlignment" Value="Center"/>
        <Setter Property="HorizontalContentAlignment" Value="Center"/>
        <Setter Property="Padding" Value="{StaticResource GenericButtonStylePadding}"/>
   </Style>

</ResourceDictionary>

App crash runtime. Because Cannot find a Resource with the Name/Key GenericButtonStylePadding???

How can i run app correctly??? Please help me