i dont really know but 1st you need to convert your texture in to .DDS and thats for sure. just google convert .jpg to .dds and you will find a tool to do it :smile:
It's Pretty simple - all you need to do is have the texture saved as a .dds file (there are plugins for GIMP and PhotoShop which will let you do it) and then, in xpacker, you just upload it under the "Textures" tab.
I think in XPacker you should go to the 'Materials' tab and click on 'Add from Textures' bottom left to add a texture. This makes the .xml files you need for it to show up in BTB.