Well that's complicated as you know. Referendum as per UN charter is not possible due to the following few reasons.
1) The UN Resolutions became un-implementable and plebiscite redundant. That is why former UN General Secretary Kofi Annan had said “that the General Assembly cannot implement the resolutions of the UNCIP.
2) A referendum ( as per all the respective resolutions of 1947-48 regarding this) include all of the Kingdom of Kashmir before August 1947, which include Jammu and Kashmir, GB, Azad Kashmir as well as the Trans-Karakoram Tract.
3) All the pre-conditions of the resolutions are to be satisfied, which both India and Pakistan know very well that it is impossible since neither will do that.
Hmm, a small correction. Those who are protesting are rather a minority, what everyone care about is the majority voice.
Moreover if the majority don't actually like India ( as claimed by Pakistan) why would they come and vote in millions, if it is an Indian administered elections. Every time the separatists call for a poll boycott to no avail. LOL