A new hostproblems with authentication

Trying to access a webservice via wcf_customhttp.  I have :

1. Set the webservice website as windows authentication only.

2. Created a new host, host instance with the correct domain credentials

3. Added a new sendhandler for the new hostname

4. on my send****t, Security Mode= Trans****tCredentialOnly , Windows

However, my webservice is always accessed as  re****ted from?
System.Security.Principal.WindowsIdentity.GetCurrent().Name "NT 
AUTHORITY\\NETWORK SERVICE" string

Any thoughts?