There are a few ways in which you can access the web service.
1. Allow the calling apps to run under a credential that can connect to the Web service layer. For an application running in Win2K or XP you can use Run As option. For a COM+ server component you can set the identity to a user who has access on the Web service layer.
2. Create trusts between the respective domains to allow user of one domain to access resources of another domain. in this case, user of the App domain should be able to authenticate to the Web service in the domain containing the web service.
3. Allow basic authentication in the Web service server and send the authentication information as the SOAP header.
For more information visit the following links:
I was wondering why you did not post this to the BDOTNET message board.