Not sure if this is what you mean, but if you are at a 9 handed table it would look like this starting with the dealer and working left.
BTN = Button / Dealer
SB = Small Blind
BB = Big Blind
UTG = Under the Gun
UTG + 1 = next person
MP1 = Middle Position 1
MP2 = Middle Position 2
MP3 also know as HiJack
CO = Cutoff
I don't think you can add it to the HUD, but you could search google for a graphic to print out and tape next to the monitor. Like others have said, after awhile it becomes second nature.
