H1B approved and traveling out of country before start date.

Currently I am on F1 status and I have my H1B approved status starting from Oct 1, 2013 from an employer.
In an emergency situation I have to go out of country before Oct 1, 2013.
In that case:

Q1) Do my employer has to run my payroll even though I have not started the employment and not present in United States?
Q2) If not revoked by the employer, can my approved H1B be used in future for the same employer?


Thank You.