navigation TreeView problem in multilingual

Hi,
    my problem is that when i changed language culture  in arabic  then all page  change LTR to RTL but  TreeView menu arrow not change.

======LTR view=======
> A
> B
> C

=======RTL view=======
A >
B >
C >

code===============

<asp:TreeView ID="TreeView1" runat="server" DataSourceID="SiteMapDataSource1"
ForeColor="White" ImageSet="Arrows">
<HoverNodeStyle Font-Underline="True" ForeColor="#5555DD" />
<NodeStyle Font-Names="Verdana" Font-Size="8pt" ForeColor="Black"
HorizontalPadding="5px" NodeSpacing="0px" VerticalPadding="0px" />
<ParentNodeStyle Font-Bold="False" />
<SelectedNodeStyle Font-Underline="True" ForeColor="#5555DD"
HorizontalPadding="0px" VerticalPadding="0px" />
</asp:TreeView>
<asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server" />

Please help me.