Having had problems installing MySQL from within WebMatrix (with either WordPress or Drupal) I removed the incomplete installation and installed V5.6 manually. This was succesful and I can administer the server with MySQL Workbench.
However when I now try to install WordPress again, with WebMatrix or Web Platform Installer, neither of them see the MySQL server and still want to download and install MySQL 5.1.
How can I get WebMatrix to see MySQL 5.6 and allow me to install WordPress and Drupal?