how to eleminate text which is appearing inside of an applicationbarIconButton's image in wp7

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WinMobile

Hi,
I have created one sample windows phone 7 application. For that i have added 3 applicationbar menu icon buttons. But the problem is the text which is given in Text attribute is appearing inside of corresponding application bar menu icon button's image. The code is as follows.

<phone:PhoneApplicationPage.ApplicationBar>
        <shell:ApplicationBar IsVisible="True" IsMenuEnabled="True">
            <!--<shell:ApplicationBarIconButton IconUri="/Images/appbar_button1.png" Text="Button 1"/>
            <shell:ApplicationBarIconButton IconUri="/Images/appbar_button2.png" Text="Button 2"/>-->
            <shell:ApplicationBarIconButton IconUri="/Images/Home-icon.png" Text="home"/>
            <shell:ApplicationBarIconButton IconUri="/Images/menu-icon.png" Text="menu"/>
            <shell:ApplicationBarIconButton IconUri="/Images/Map.png" Text="map" />
            <!--<shell:ApplicationBar.MenuItems>
                <shell:ApplicationBarMenuItem Text="MenuItem 1"/>
                <shell:ApplicationBarMenuItem Text="MenuItem 2"/>
            </shell:ApplicationBar.MenuItems>-->
        </shell:ApplicationBar>
    </phone:PhoneApplicationPage.ApplicationBar>

could you please tell me solution for this.