The portrait file for the theme selector is Player_Portrait_Large.tga located in your Textures folder.
It should looks like
this. Each column is the set of 3 portraits you toggle between, and each row is the race (TEC, Advent, Vasari from top to bottom).
If the Vasari portrait shows TEC, then the appropriate theme file is in your Window folder, called PlayerPhase.playerPictures, and it should look like (open in Notepad):
TXT
pictureCount 6
LargeScreenPicture
textureName "Player_Portrait_Large.tga"
startTopLeft [0,444]
width 195
height 219
rowItemCount 6
horizontalStride 198
verticalStride 222
...
Basically, this file splices the above .tga. In this case it starts at x=0 y=444, top left corner of the third row, sets the width and height, and then splices the row into 6 images 198x222.
So that's why the only reason I can see for your theme picker showing up as TEC for the Vasari is either if the .tga isn't proper, or if the playerPictures file points to the first row instead of the third.
Hope this helps, pretty odd issue