Ok, the ways to have Custom hostnames instead of IP addresses in self-referencing links are referred here: https://secure.centova.com/pages/faqs/display/custom_hostnames_instead_of_ip_85

my streaming provider tells me:
"In regards to the custom hostname issue, I can confirm we have made the necessary changes to our servers however it did not fix the issue. I am still waiting on Centova Cast at this time, I can only apologise but there is little we can do as we do not modify the software we run."

any help from Centova please?