Strange that there is so little information about the place.
You could always try contacting a local business, e.g. a Shipka hotel like
they have some meagre details on it on their website but they may be able to give you info. on conditions
or http://www.visitbulgaria.net/en/buzludj ... hotel.html
Or, type in something like "Buzludzha peak skiing" in http://www.google.bg
and see what comes up or even use "Buzludja" or "Бузлуджа"
Or, try contacting someone at http://www.bulgariaski.com