Also the Secure Login Implementation Guide for SAP NW SSO says the Secure Login Library can be downloaded from this area in the support portal and I couldn't find SSO 2.0 under SAP NW and complementary products.
Software Downloads -> Support Package and Patches -> Browse our Download Catalog -> SAP NetWeaver and complementary products -> SAP NetWeaver Single Sign-On -> SAP NetWeaver Single Sign-On 2.0 -> Comprised Software Component Versions -> Secure Login Library 2.0