When I register a domain, I typically have to wait 2-3 days before submitting it to Sedo, or else their system can't confirm me as the owner. I don't know why the lag is so long.
At worst, you'll soon get an email from them asking you to prove that you own it. You can either send them an email from that domain's administrative address or else change the DNS to the Sedo parking nameservers.
Good luck!
Dave