H1B Transfer - New employment start date

[gababo]

Sir,

I've been working for my current employer since 10/1/2009, and I recently received another job offer with starting date of 9/22/2011. Because today is 9/2/2011, I have about 20 days. I've already already talked to my prospective employer about H1B Transfer. I assume my prospective employer has to apply a new LCA certification even though my current LCA certification has more than 365 days (until 9/24/2012). Is my assumption on a new LCA correct?

Also, it's possible to begin to work for my new employer on 9/22/2011 if I-129 package is delivered by at least 9/22/2011? H1B portability provision uses "filing date," but its term is kind of confusing. I read other posts regarding this date, but want to make sure that I can begin work as long as the I-129 package is delivered to the INCIS service center.

Your advice would be greatly appreciated.

Thank you.