Exemption u/s 54f of income tax act

Dear friends pls clarrify me regarding the following query...

Mr. A owns one Residential House Propoerty containing 2 floors and also owns one plot of land ( Long Term Capital Asset, Cost Rs.100000). Now he wants to sell the plot of land for Rs.700000.

After selling the plot of land he wants to invest the sale consideration in purchase of residential house property for Rs.30 lakhs to claim exemption U/s 54F of IT Act.

But Mr.A  wants to Register the new house property under joint ownership in his name along with his sons name.

Releavant Points:

A) Investment of Rs. 30 Lakhs in New Resi House Property is arrived out of funds from a) Sale proceeds of 7 lakhs b) salary savings of Rs. 13 lakhs and c) Housing loan in the name of his son of Rs. 10 lakhs.

B) Registration under joint ownership is made to secure housing loan of Rs. 10 lakhs in the name of his son.

C) Housing Loan of Rs.10 lakhs in the name of his son is taken to avail the interest exemption U/s 24 and principal dedcution U/s 80C.

So friends pls clarrify me...

1) Whethere Registration under joint ownership would dis entitle Mr. A to claim exemption U/s 54F

2) and new housing loan in the sons name would dis entitle Mr. A to claim exemption U/s 54F.

Thanks in advance.