IIS 5.1 Wildcard mapping breaks AJAX

Hello,

I have Wildcard mapping set up on my IIS 5.1 on my XPPro machine.
This is used along with urlrewriting.net to get .aspx less urls.
this all works fone, except it breaks ajax.
if i remove the wildcard mapping then the ajax works fine.

The mapping looks like this: (in danish, but it should be understandable)



and this is my pagemethod:
    <WebMethod()> _
       Public Shared Function TestFunction() As String
        Return "yubii"
    End Function 'CheckUserName
  
This is my Javascript:
 // Check username against the webservice

        function CheckUserName(UserName){
    & ...