Ca final may 2015

Yes, you can send your form on the provisional basis.

In the exam form, where the column ask for date of registration, write the date of sending the application for Registration.

They will take time to register you,15-20 days. So, don't waste the time waiting for your Registration Letter.

They will surely issue you admit card. They will verify your registration in March-April, which you have already applied for. 

I personally have faced the same situation.

Worked for Me !

YES you can apear for May 15 exam.

BUT PLEASE DO NOT MAKE THIS MISTAKE. I ALSO MADE A SIMILAR MISTAKE IN NOV, 2011 EXAM.

Your attempt will be counted and every attempt after this will get counted. So give exams only after you are well prepared,