#1 - Sept. 10, 2014, 12:33 p.m.
Login to https://eu.battle.net/account/management/
Click on your main, retail account.
Click the additional services tab at the bottom, and select Public Test Realm.
You'll get a message about PTR Character Copy is in Maintenance.
Click History/Status
Log out of the Battle.net Account Management website, and re-launch your Battle.net App.
This should force a WoW PTR game account license onto your Battle.net account. If it doesn't, let us know.
Potential Additional Troubleshooting step: Next to the History/Status tab in Account Management, Click the Download PTR Client tab, and then click on the Installer for Public Test Realm. This should just re-launch your Battle.net client, but it may be what you need to get it to show up there.