CalendarExtender change month

I have 2 date textbox controls (see below) using ACT. When I click on the textbox I get the calendar for the current month.  If I enter a date for a different month in the first textbox (txtTimeOffDate) I want the 2nd textbox (txtTimeOffDateTo) to popup the same month calendar instead of the current month.

<td><asp:TextBox ID="txtTimeOffDate" runat="server" Width="72" ClientIDMode="Static" onchange="setdateto(this);" /><cc1:CalendarExtender ID="CalendarExtender3" runat="server" TargetControlID="txtTimeOffDate"></cc1:CalendarExtender><asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" 
                            ErrorMessage="Time off Date is required." Display="Dynamic" 
                            ControlToValidate="txtTimeOffDate"></asp:RequiredFieldValidator></td><td><asp:TextBox ID="txtTimeOffDateTo" runat="server" Width="72" ClientIDMode="Static" /><cc1:CalendarExtender ID="CalendarExtender4" runat="server" TargetControlID="txtTimeOffDateTo"></cc1:CalendarExtender></td>