[2005] Secure Webservices using ASP.NET

Hello ,
i am interested in creating a secure asp.net webservice.
The channel should be encrypted and it would be good if there are client certificates.
In order to do channel encryption do i have to simply
check the "Require Secure Channel" checkbox in the "Directory Security" tab of IIS ? Do i have to also create a new server certificate for my server and a client certificate for my server also ?

Do you have any links with information regarding this issue ?

Thank you very much !
alexander

Considered SSL?

http://msdn2.microsoft.com/en-us/library/w67h0dw7.aspx