Call the broker, ask them to allow the trade before funds clear and have them do it for you while you watch your account. Tell them you might miss a buying opportunity, and ask them to charge the normal online rate.

Fidelity has done this for me re: BLTA 2 or 3 time in the last year. They say, "happy to help you, but please don't make a habit of it."

You are their customer...give it a try!