I think he means when you download a set from the internet like at Inferno. You leave and reenter the garage (not pits) after downloading or as AndroidXP says, change cars and change back (if not single car server).
Only problem with that is you then can flood the ingame chat with system messages "[RCG]Boosted has entered the pits.... [RCG]Boosted has left the pits.... [RCG]Boosted has entered the pits...." It could be annoying to those others who haven't had the frame of mind to delete the system message and chat message sounds.
Actually, no. It shows up in the garage even if you were in the garage when you downloaded the setup? If so, this suggestion is redundant. I'll try it out.
Edit: You were right I guess a refresh-button isn't really necessary :P