Siebel 7.8 to Oracle BI publisher integration.

Hi all,
I am trying to integrate Siebel 7.8 application with Oracle BI publisher for reports generation. Here's the deal : Users will not log in to BI Publisher at any point. They will click a button and an outbound integration from Siebel to Oracle BI should happen and the resulting pdf should pop up in Siebel.
Has anyone out there tried this out or know how this can be done ? Oracle BI does not have a concept of IO and the only WSDL it generates is very generic.