I don't expect so. SAP is trying hard to make the support experience consistent for all products.
Most of the old Sybase.com public resources have already been decommissioned and I expect the remaining ones to go away in the future.
The ASE 15.7 SP130 Guide is available through the "Documents" section of http://support.sap.com for customers with a support contract. A direct link is http://help.sap.com/Download/Multimedia/zip-asecluster/ase_whats_new.pdf (don't be thrown off by the "cluster" reference, the document describes general new features as well as the ones specific to ASE Cluster Edition)
-bret
