Strange, it works for me. Did you replace the old shape with the new one? Also as Foreverk has said you have to flip the tex file.
Step 1: Convert the tex file to a tga file
Step 2: Use a photo editor to flip the file vertically
Step3: Convert the file back to a tex file
Step4: Place the helmet in the right driver file you want to replace with it named correctly. Like Driver17_1
I hope this helps and is not too confusing.
Good Luck.