RadDatePicker validation

[coderapp]

Hi

Using RadDatePicker and calendar popup for my application, but having hard time validating it.
To disable any input i used DateInput-Enabled=false.

I have two fields
Date Created and
Date Completed

The validation i want to do is
Date Completed should not be less than Date Created.

not able to set Minimum in DateCompleted to DateCreated
The code is


<tr>
<td><radCln:RadDatePicker ID="DateCreated" runat="server" DateInput-CausesValidation=true DateInput-Enabled=false DateInput-ForeColor="Black"></radCln:RadDatePicker>
</tr>

<tr>
<td><radCln:RadDatePicker ID="DateCompleted" runat="server" DateInput-CausesValidation=true DateInput-Enabled=false DateInput-ForeColor="Black"></radCln:RadDatePicker>
</tr>



Thank you