Manually Defined Delete Command Doesn't Work

Hi,

 i defined a sqldatasource in VWD manually (option specify sql statement) because several tables are involved. I also need a Delete statement, so i defined it also manually.

The select and delete statement are :

 <asp:SqlDataSource ID="SqlDataSource1" runat="server"
           ConnectionString="<%$ ConnectionStrings:test %>"
          
           SelectCommand="SELECT aspnet_Users.UserName as lid, aspnet_Roles.RoleName
           as categorie, aspnet_Users.beheerder as beheerder, aspnet_Membership.Email as emailadres FROM aspnet_Users INNER JOIN
           aspnet_Membership ON aspnet_Users.UserId = aspnet_Membership.UserId INNER JOIN
           aspnet_UsersInRoles ON aspnet_Users.UserId = aspnet_UsersInRoles.UserId inner JOIN
           aspnet_Roles ON aspnet_UsersInRoles.RoleId = aspnet_Roles.RoleId order by username"


           DeleteCommand="delete from aspnet_users where userid=@userid">
            <DeleteParameters>
                <asp:Parameter Name="userid" />
            </DeleteParameters>
       </asp:SqlDataSource>

My problem is that the Select works, but not the Delete.

Any idea why?

Thanks

tartuffe