NAV Webservice in different language / date format

Hi,

I have implemented a Codeunit webservice in NAV2009 and passing a date as an argument to a method. I would like to have influence in what format the date is handled and i was assuming that the dutch language module could help me out. But that seems not the case.

I have changed the regional settings for the user that runs the NAV Server + Nav Server Webservice. but still same error.
The error i get:

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/&quot; xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance&quot; xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
  <soap:Body>
    <soap:Fault>
      <faultcode xmlns:q0="urn:microsoft-dynamics-schemas/error">q0:Microsoft.Dynamics.Nav.Types.Exceptions.NavCSideException</faultcode>
      <faultstring xml:lang="en-US">'13-11-2014' is not a valid date.</faultstring>
      <detail>
        <string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">'13-11-2014' is not a valid date.</string>
      </detail>
    </soap:Fault>
  </soap:Body>
</soap:Envelope>

Is there a way that i can set the culture information like webservice in IIS can have?
<globalization culture="nl-NL" uiCulture="nl-NL"/>

ANy other ideas how to fix this thing?