Transitioning from Corporate Office to Independent - How To?

Hi all. I work for a large multinational corporation as an unlicensed freight brokerage agent working under their authority and with their customer, carrier, and related information base at my disposal. My book of business is a company held one. I know there are ways to do this same work independently, and that is what I am pursuing, as I know it is much more lucrative. I have had interviews and talked to brokerages that turn me down because I do not have my own personal (and not company held by my employer) book of business. The thing is, I do, I just couldn't take it with me.

I am seeking the best and most recommended way to move forward. Do I contact local shipping leads, let them know what I am trying to do, and offer contingencies of service if I have them as part of an existing and "portable" book of business that I would be bringing with me to a brokerage? Is there another more recommended option that anyone can think of? Do I shell out the big bucks for training (If so, where? I know there are a ton of programs out there...)? Just making sure I am doing this in a 'smarter not harder' way.

Any and all advisement on how t properly proceed? Please let me know. Thanks!