H1B transfer after H4 to H1B approval in Nov 2012


Please answer my queries even though those look repitative, I have gone through Q/A forum but did not get satisfactory answer.

I have filed for H4 to H1B transfer and got H1B approved yeasterday for employr A. I also have other employer B where I can transfer H1B.

  1. I have not started working for my current employer A , I do not have any paystubs. So within how many days/months my H1B can be transfered to employer B?

  2. What if the H1B transfer is denied or I get RFE? Can I start working for my current employer A?

  3. I will be applying for SSN soon with current H1B approval copy, so can this H1B transfer effect SSN process (if I file for H1B transfer when SSN is in process)?

Please reply my queries asap. Thanks in advance.