nishant,
I am going to disagree with Q slightly on this one.
If you return using AP, you will be a Parolee and this is evidenced by the I-94 that is issued when you return.
Due to the legacy Cronin memo, if you are returning to work for your H1B employer, you are allowed to continue using the Employment Authorization component of the H1B approval and do not need to use EAD.
This is not the same as being in H1B status. This could be important, if for example there are H4 dependents relying on the H1B older maintaining H1B status.
The H1B approval remains valid and it is possible to return to H1B status.
You can return to H1B status by either leaving the USA and returning using an H1B visa, or when an H1B extension (with attached I-94) becomes effective.
The Cronin memo can be found here
http://shusterman.com/h1blvisasmemow...nceparole.html
A really good article explaining it is on the Murthy site here
http://www.murthy.com/news/n_efftrv.html
To answer your questions, yes you can use AP and then at a later date get the stamping and re-enter using your H1B visa.
I don't know the answer about transfer, but that does seem possible and indeed the Murthy article says it is, since it is really only an amendment/extension request.
As always, consult a lawyer when dealing with important issues.