Installation: How to get the right license for Vivado 2015.4

• After having created an account on www.xilinx.com, go to https://www.xilinx.com/member/forms/license-form.html.
• Fill out your name and address and click "next".
• select Certificate Based Licenses/Vivado Design Suite: HL WebPACK 2015 and Earlier License
• click Generate Node-locked license
• click Next
• get congratulated for having the new license file 'xilinx.lic' mailed to you. Download the license file and import it with Xilinx license manager.
• for later download: the license appears under the tab 'Managed licenses' with asterisks (*) in each field except for 'license type'='Node', 'created by'='your name', and the creation date.

Voila!

This problem is also discussed in issue #272 with screenshots of successful installations.