Registration of an educational trust

I am the joint secretary of an educational trust in Karnataka that was registered under The Bombay Public Trust Act,1950 in the year 1952. Govt.of Karnataka repealed the BPT act in 2001. No enactment has so far been made for governing educational trusts. I have been insisting on registering the trust under The Indian Trusts Act, 1882, as section 5 of the said act says that any trust having movable and immovable assets is not valid unless registered. The trust in question has both movable and immovable assets.Some of the trustees say that their personal lawyers are of the opinion that the trust need not be registered under The Indian Trusts Act. However, they are not willing to put their opinion in writing. Hence seek guidance from your forum whether it is mandatory to register the trust under The Indian Trusts Act or it can continue to remain an unregistered body.