Looking for a document in order to implement SSO between the portal and BW

Hello,

We are running on portal EP6SP16 with Kerberos Authentication using SPNego.

I am looking for a good step-by-step document which will help me to understand and implement an SSO between the portal and a BW server we have.

And one more thing: Even though I am very much familiar with the portal side I hardly ever worked on the BW side therefore I will need more documentation in case there are things that needs to be done on the BW server itself.

Can someone please refer me to such documents?