I unterstand that. But I have a few Snom phones now where the provisioning link points to the url/rps/cfg {mac} link and they don't seem to receive anything through provisioning. This is behind a SBC. They come up asking for the registrar, user and password and then they register. But with no BLF config or idle screen.
So the phones were provisioned as Remote Stun phones but are behind an SBC? What is the provisioning method chosen under the extension settings / phone provisioning? If you make a change to the extension settings like the name of the extension and re-provision do you see that change applied?