If I am not wrong then conversion happens in uplink station(means on earth), it is not happening in space(satellite) which is we can think as a reflector(like a mirror). That reflector reflects the beam back to earth whatever we beam to it but of course at different freq to avoid interference.
TPs is converted to DVB s2 means all channels are coded in this coding method by uplink station before uplinking to satellite.
DVB-S2 is a television broadcast standard which is advanced than DVB-S... it has support for H264 video codecs... and hence can support HD channels... A DVB-S2 TP can perform better (atleast 30-40% more) than a DVB-S TP with same bandwidth... converting a TP to DVB-S2 means, now TS can shuffle the HD channels to any TP or can add more SD channels in a TP than it is now.. and that means they need not hurry to change satellites... :k:k:k