I dont know if this has been posted before but it appears that Sony can add applications and weblinks to XMB using XML while trying to get around the 3.21 firmware lock out I installed PS3 proxy server and followed the tutorials but when the PS3 connected to the PSN it downloaded this file.
It appears that the PS3 only downloads this file every so often ( I tried redirecting the Iplayer link to Youtube and it didnt work)
I managed to change the Now TV link countries location to "UK" and it appeared on my XMB but only when I logged into the Hong Kong PSN. (It didnt appear when I logged onto the Hong Kong PSN just before hand)
My guess is that the PS3 checks the server and decides to download the updated TV services XML file every so often. But also allows for the possibility of the Now TV PKG to be replaced with another PKG file which might be a way of getting PKG files installed onto the XMB.