Bringing 'Atta' concept to Buddha's teachings We have seen many researches and references (like "Reviewed Work: Self and Non-Self in Early Buddhism" and many more supporting documents from PTS, Pali text society) that the idea Atta to some extent it exists and can be deduced that Buddha's teachings also consists of "the idea of Atta". The popular references by I.B Horner (need citation here) and some scholars is 


  atta hi attano natho


In Buddha's teachings and Tipitaka, I do not see a slight extent of existence of Atta or some ambiguities about Atta by Buddha or monks at the Buddha's ages. All Buddha teachings are ubiquitously about Anatta. And Gautama Buddha repealed the very concept ’Atta’ in many Suttas. Since his second discourse “Anatta Latkhana Sutta", Buddha’s teachings are all about Anatta. Anatta is key concept in Buddha's teachings and Gautama Buddha was first and very first person opposite and challenged to popular Atta idealists at the age of his time. My question here is why some scholars and some publications from Pali text society are trying to coerce Atta concept in Buddhism or society of Buddhists?  What are the supporting facts that Gautama Buddha and his teachings are self denial to its own Anatta concept? What are the proofs that Buddhism accept/adopt Brahmanism's Atta idea since both are clearly opposed to each other? 

Please keep in mind that the words self and not-self are loosely translated, have ambiguous meanings about referring internal and external based on perspective of particular individual being and not applicable/intended words here. Atta and Anatta is what I am referring here.    

The definition of Atta

Atta is the word from Brahmanism, it is essence, from Brahma (or whatever creator make it exists), eternal or indefinite period of existence, it has capability of suffering pleasure and pain. It is in each and everyone bodies and pass from life to life. Some outside Buddha’s teachings define Atta as ’soul’ and/or self but precise definition of Atta is highly controversial.
It is possible to bend the Buddha's message (if you so wish to do) because the Buddha never denied Atta in an Essential sense, he only pointed out that within empirical experience (all the way up to the perception of cessation) no 'thing' can be said to be constant and unchanging, as a self would be required to be.. hence the Mulapariyaya Sutta.

Whilst the Buddha was very clear with regards to the lack of evidence for Atta within the empirical world, the Brahmajala and Potthapada Suttas shows that with regards to the Transcendental Atta (which is the Atta that most darshanas went for - Brahman/Atta is usually seen as beyond experience, commonly stated as 'neti neti' - 'not this, not that'), he asked people to avoid speculation (because whatever that 'transcendental' is inferred to be, it cannot be perceived and therefore cannot be verified)

The Anatta doctorine is very subtle, a not insignificant number of schools of Buddhism have gone towards either essentialism (brahmanism) or annihalationism (nihilism) at some point. Yogachara has the nature of Parinispanna, which is a transcendental Atta. Mahayana developed the Tathagatagharba, which makes the Buddha a kind of Atta for Existence. The Buddha would have likely not concurred with these though!