H1b "transfer" before 1st oct, 2013

Hi, Here is my situation: Current status: Stem opt till nov 2013, working for employer A, work is unpaid until h1 starts, so no paystubs H1b status: h1 was filed by employer A and got approval notice last week. My h1 with employer A starts on oct 1st. I want to switch to employer B starting July 1st. and they can do premium. Will my h1 filed by Employer B be subjected to cap (which is already over)? If yes, then there is no point in changing employers. If no, then can I do this “transfer” without paystubs? All inputs are greatly appreciated.

B’s petition will be cap-exempted based on A’s approval notice.

However, you need to confirm if you are maintaining status while on OPT. Unpaid work on OPT is allowed only if there are other people doing similar jobs for free for that employer. It should not be a sham to hide unemployment.