For version 12 download (Developer Edition, Eval Version and SP), you must use the SAP SCN and/or SAP SMP.
For some of this download you need a S-User ID, which will provided to SAP partners with contract. If you have a valid Sybase Partner contract, you can send me your details, so we can check, why you don't get your S-User ID.
Currently, without a S-User ID, you can only download the XE10 support for V11 on DevZone.