There's a login for the PreSonus Global Navigation for your my.presonus.com account.
However Answers does not have a Single Sign On feature, so just click on the "Green Answer" or "Ask A Question" link in the toolbar to see the Login Prompt. Just click Login and your session information from my.presonus.com will log you into the Answers site. Then the buttons you're looking for will appear.
If you sit idle for more than 10 or 15 minutes, the system may log you out due to inactivity.