They are in default\gamedata\uniticon.txt and \english\gamedata\tips_str.txt Line: 388 in uniticon.txt
ICON_TILEIMP_PILLBOX { FirstFrame "UPTP085L.TGA" Movie "NULL" Gameplay "TILEIMP_PILLBOX_GAMEPLAY" Historical "NULL" Prereq "TILEIMP_PILLBOX_PREREQ" Vari "TILEIMP_PILLBOX_STATISTICS" Icon "UPTI085D.tga" LargeIcon "NULL" SmallIcon "NULL" StatText "NULL" }
ICON_TILEIMP_BARBEDWIRE { FirstFrame "UPTP088L.TGA" Movie "NULL" Gameplay "TILEIMP_BARBEDWIRE_GAMEPLAY" Historical "TILEIMP_BARBEDWIRE_HISTORICAL" Prereq "TILEIMP_BARBEDWIRE_PREREQ" Vari "TILEIMP_BARBEDWIRE_STATISTICS" Icon "UPTI088.tga" LargeIcon "NULL" SmallIcon "NULL" StatText "NULL" }
End of tips_str.txt:
# Added for WWII Scenario
STATUSBAR_TILEIMP_SELECT_PILLBOX_BUTTON "Pillboxes can be placed on any land-based tile."
TOOLTIP_TILEIMP_SELECT_PILLBOX_BUTTON "Pillbox"
STATUSBAR_TILEIMP_SELECT_BARBEDWIRE_BUTTON "Barbed Wire Fence can be placed on any land-based tile."
TOOLTIP_TILEIMP_SELECT_BARBEDWIRE_BUTTON "Barbed Wire Fence"
I think you also have to copy over the gtset555.til and gtset565.til files from the scenarios\ww2\scen0000\default\graphics\tile directory over to your \default\gamedata\graphics\tile directory. This is the tileset files used to determine tile and improvement graphics (i think)