I was asked what the procedure was, not to inventory the personnel available to do it.
My experience with depositing certs was not as easy as you describe. Perhaps you have better contacts than I do.
I had an unrestricted cert from an OTCBB bank that is trading in the $20 range.
TD ameritrade E-trade Scott trade and two others I contacted would not take it.
Two of those companies had me endorse and send the cert, then refused it and I had to have the cert reissued.
Finally Merrill Lynch took it.
I never tried Interactive Brokers as i was unaware of them at the time.
A complicating factor was that the bank is acting as its own TA. The good news is that I could drive to the bank and get a new cert issued in 48 hours.
Maybe that the bank was acting as it's own TA was the problem.