I am currently employed in Company A on a H-1B visa. Recently, I have been offered a job by Company B with a joining date of Sep 16, 2011. But the Company B has cautioned me that - for the H-1B visa transfer to be legally valid, my last date of employment in Company A must be Sep 15, 2011. Is this true?

On the other hand, I have 10 vacation days available in the job at Company A that requires a 2-week notice period for resignation. Can I resign on Sep 01, 2011 and use the notice period in Company A for vacation time of 10 weekdays upto Sep 15, 2011? This will give me adequate time to make an out-of-state move and settle in the new house & new city before the Sep 16, 2011 start date at the Company B. Is this fine with the new H-1B visa transfer rules?