Authenticating with Sql Server using domain account as app pool Identity

I am trying to use a domain account for an Isolated IIS 6 app pool Identity. The app pool runs the asp.net 4.0 frame work app fine and authenticates to sql fine from code using integrated security. However when I try to load a crystal report into viewer or stream to pdf crystal reports a database login failure, displayed in top of viewer control. Running a trace against the sql database there is no login attempt being made before the failure occurs.

I do not want to impersonate the logged in user. I just want to control access to the database using the app pool domain account as the login.