Removing the Surname requires hiding it. In reality your HP par has a "built in" lable tag. That's the name your see in the Player Info window.
To remove it, change the size of the HP bar to 108x8. *Edit* Oops, forgot. Also change the TextOffsetY to 30 or something greater than 9.
Now, to Put your name back in. This requires creating a new Lable of EQType 1. Create that and just place it back up top there. X,Y cords will be 3,0.
I forget the size though. To test that, keep out the EQType tag and it will place Player123456 in there. Size it until it works for you, then put back in EQType.
Hope that helps ...
*Quick Epic .. see above*