that's only because sc_trans isn't passing that information on at the moment - is one of the common requests from the last few months with regards to wanted sc_trans updates (is quite a few threads / posts which have been made about it
personally i don't think it's worth it as people have used it as a hackish way to determine the DJ in use and probably things should be done in a more formal manner in the tools but then that involves getting people to use the newer tools to be able to use it.
for example, sc_trans or dsp_sc could send the user-name in the metadata sent or leverage the username provided in the connection to the DNAS / sc_trans's DJ handling, but then that requires doing other changes later down the line to ensure that it is available to be queried from the DNAS.
so sadly at the moment it seems like keeping with the old aim/irc/icq usage is the simplest way to not break too much in order to get people onto the newer versions of the tools.
then again, maybe i should just go ahead and implement and if it is used or not then it's down to users and not something which is waiting to be implemented in the tools as i'm not in favour of re-enabling the IRC/AIM/ICQ options in dsp_sc as is when it's in v2 mode, so maybe the use of the DJ name is going to better overall...
note a load of edits to my original post