For usability it is nice to have on the login page below the login submit button:
"Not member yet? Click here to register."
And on the register page a link below the register button:
"Already member? You can login here."
This can only be done by changing the files:
pages/login.php and pages/register.php
Adding a $qa_content['custom'] = '...' after the $qa_content['form'] blocks.