How to submit proofs of last minute investment done under section 80 C ?

I am salaried employee in private software company. As per company policy we have to submit proof of investments done under 80C before 25th January 2015. I want to invest in schemes under 80 C in the month of February-March 2015. So Eventually my all investment details under section 80 C will not be reflected in form 16 since I have not declared it with my employer.

Now, while feeling online ITR-1 form, shall I declare all the investments under 80C or only those mentioned in form 16 given by employer ?

Do I need to send the zerox proof of all investments made in financial year along with ITR-V form while sending it to IT department, Bangalore? 

What are the steps I need to follow to declare those investments which are not present in form 16?

Thanks in Advance. Request to Please respond.