This is a usability issue only. After a fresh install of Eclipse Classic (3.6.1) on Ubuntu and PyDev 18.104.22.1681010200, the debug menu often does not include "Debug As… PyDev: Django". If I right-click on my project in the project explorer and visit the Django submenu, without clicking on anything, I can go back to the debug menu and "Debug As… PyDev: Django" is there.
Also, if you right-click on PyDev Django in the Eclipse Debug Configurations popup, and select "New", the New_configuration created is totally blank and it would be quite complicated to fill in all the values. I found the only practical way is to run "Debug As… PyDev: Django once so it automatically creates a useful debug config (all values filled in); you'll see that new configuration in the Debug Configurations popup and you can "Duplicate" it to make your own.
Perhaps all of this is as per design… in which case the manual http://pydev.org/manual_adv_django.html might be improved.