Credentials from IIS to Exchange

Hi All

I have some problem to create an EMail on Exchange 2000 from a IIS
Webservice with Webdav. The Problem are the Credentials from the
Webserver. When i create an Email without a Webservice, this is no
problem. 

Has anybody a solution for that problem??? Connecting Excahnge via
Webservice .....

Thanks  

Best Regards 

Daniel Scherrer
InnoSolv AG, Ikarusstrasse 9, 9015 St. Gallen
Tel.    071 314 20 00