No supportings shall be attached with your IT return. Simply fill up your ITR-1 and file. As per the instructions, any attachments(including Form-16) with ITR will be returned back to the assessee by the Dept. across the counter
However, keep all your additional savings details in your record for filing with Dept. as and when called for.
Information about savings will be usually supplied to the Employer before Feb end of every year. If an employee opts for additional savings in the month of March, these details will not be captured in Form-16 and that doesn't mean that one cannot claim the benefit. Also, it is not mandatory to reveal all savings details to the Employer.