I made a cosmetic for TF2 that modifies the Soldier's face. I used the player model and sculpted in Blender from there. Once happy with the result i removed the rest of the body that is not required leaving only the chin, which is what i modified.

In Blender, all the shape keys work perfectly. I pressed CTRL+P with the model and armature then clicked "Using empty groups". I assigned the cosmetic to bip_head.

I exported it as an .smd file. Then I went to tf2 and loaded it in the Workshop Tools.

The model follows the head movement which is good, but facial expressions are not working. I realized when I exported the .smd it generated a .smd file and a .vta file, and the .vta file contains all the shape keys. The problem is that I need the shape keys to be in the .smd so I can upload it to the Workshop. Any clue?