Re-entering US with OPT before h1 b start date and H1B is approved

[bsri]

I am currently on an OPT that ends Jan 2009 and I would need to travel to India in the next few months. I had a question - If I apply for my H1 B visa in April and get it approved can I re-enter the US on my OPT before the H1 B visa start date of October or is my OPT invalidated. ( I dont plan on getting my visa stamped for the H1 Visa )

Thanks