Your query is not clear to me. In sum and substance, whether you want to know about affiliation of an unregistered Trade Union to a Federation of Trade Unions with ideological unity OR about the recognition of an unregistered Trade Union by the employer of an organization where the union functions.
10th January 2018 From India, Salem
15th January 2018 From India, Haldwani
The cryptical fashion of framing of questions some times tempt us to give answers other than what exactly sought for. That's why I raised some queries in my first reply and the poster also responded affirming the question he actually intended. Since the affiliation of any union to a Federation of trade unions with ideological unity is a simple and formal transaction between the centralised and individual association of employees so as to enhance the power of bargaining of the latter, registration of the trade union under the Trade Unions Act,1926 or under any other Act like the Societies Registration Act,1860 would be the only precondition. The link you've cited confirms this for which I should certainly thank you. As rightly observed by you, recognition of the individual union by the employer or not is not at all an issue in the process of affiliation.
15th January 2018 From India, Salem