Single sign-on from Domino to SAP Portal

Does anyone use either SSO or SAP “tickets” to implement single sign-on between Domino and SAP Portal?

Our aim is to have users log into Domino, have Domino create a certificate (“ticket” in SAP-speak) in the user’s browser, and then when the user clicks on a link to the SAP Portal, SAP recognises and trusts that the certificate, matches it to the equivalent SAP user identity, and allows the user to work in SAP portal with the rights of that SAP user as normal.

It works the other way (logging into SAP portal and having Domino trust SAP’s credentials without prompting for a login), but I’m not so sure about going from Domino to SAP.

Reference material:

http://help.sap.com/erp2005_ehp_04/helpdata/EN/a5/efee7e3342354d9d1ac8d1a3399632/content.htm

Thanks!