I would not advise you to just go wandering into the Afghan Refugee camps just like that. I had a pashtun friend from England who went to an Afghjan refugee camp to give them some money and provisions. He was lucky to come out alive. He was literally pounced upon by them and whatever he had was forcefully taken off him, even his own money …he was lucky to walk out with his own shoes and clothes in one piece.
That was an Afghan refugee camp in Peshawar. i am not sure how those you mention are. I am not sure what practical advice your pakistani friends from Spain can give you. I am not sure if they have travelled around Pakistan.
I know where Ghazi is but where are Panian, Padhana, Basu mera? There are plenty of Afghan refugees on the western side of Islamabad/Pindi in Pir wadhai. There is a small camp there.
If your going to travel with photographic equipment there i would advise you to join flickr - there are a number of pakistani photography groupson www.flickr.com, many which are very active. The people come form all walks of life except the poor/very poor backgrounds. I could put you in touch with some people if need be.