SAP logon ticket creation without EP/XI

We are trying to perform SSO from a MOSS 2007 app into a backend SAP system directly. I have seen the posts commenting "there is no DLL that creates a SAP logon ticket for you. You need an SAP NW Application Server as an ticket issuing system" but for the most part they seem to indicate using the EP as the ticket issuing system.

My question can be generically asked as - if someone is not using the EP or using XI and wishes to call a web service on a backend SAP system directly (let's just say ECC 6.0) how/where can we create a SAP logon ticket for SSO?