Ok, I've solved it by myself:
<style targettype="Button">
<setter property="Template">
<setter.value>
<controltemplate targettype="{x:Type Button}">
<border x:name="border" borderbrush="{TemplateBinding BorderBrush}" borderthickness="{TemplateBinding BorderThickness}" background="{TemplateBinding Background}" snapstodevicepixels="true" cornerradius="5" tag="{TemplateBinding Background}" xmlns:x="#unknown">
<contentpresenter x:name="contentPresenter" focusable="False" horizontalalignment="{TemplateBinding HorizontalContentAlignment}" margin="{TemplateBinding Padding}" recognizesaccesskey="True" snapstodevicepixels="{TemplateBinding SnapsToDevicePixels}" verticalalignment="{TemplateBinding VerticalContentAlignment}" />
</border>
<controltemplate.triggers>
<trigger property="IsMouseOver" value="True">
<setter property="Background" targetname="border" value="{Binding ElementName=border, Path=Tag, Converter={StaticResource BTHC}}" />
</trigger>
<trigger property="IsPressed" value="True">
<setter property="Background" targetname="border" value="{Binding ElementName=border, Path=Tag, Converter={StaticResource BTPC}}" />
</trigger>
<trigger property="IsEnabled" value="False">
<setter property="Background" targetname="border" value="{Binding ElementName=border, Path=Tag, Converter={StaticResource BTDC}}" />
</trigger>
</controltemplate.triggers>
</controltemplate>
</setter.value>
</setter>
</style>