If you have previous experience in EJB then i dont think you need any think else other than HF EJB. Just buy a simulator from Whizlab or Enthuware.(cost �11)some 200 questions.
I will suggest Enthuware because i have used it befor for my SCWCD and I find it very useful. I am also preparing for SCBCD exam but I am refering two books. HF EJB and SCBCD Exam study kit by paul Sanghera. it is also a good book.
you can try following links and i hope it might be useful for your preparaion. http://www.ejbcertificate.com/
register yourself and it is free. http://www.gayanb.com/scbcd_practice_questions.php http://java.boot.by/bcd-guide/ http://www.certgear.com/products/info/scdjws.htm http://www.eplanetlabs.com/scbcd.html
all the best for your preparation