BI Publisher JBC Connection Proxy Authentication

I am trying to use Proxy Authentication for a JDBC connection in BI Publisher. When creating the connection, the test connection works successfully. When trying to use it in a data model, I am receiving an ORA-01017: invalid username/password; logon denied error message. I worked with our DBA and using SQLPLus I can log onto the database as a proxy user. It seems the database is configured correctly. My question is,  how is the USERID/PASSWORD obtained for the proxy server? Thank you.