Help with coaching a vaulter to get vertical

[GHSvault]

Relatively new vault coach and running into a new problem with one of my vaulters. Tried and tried some more to get this vaulter to a vertical position, however, his feet keep coming out once the pole starts to uncoil. My simple explanation is that his head is unwilling to drop which prevents him from fully getting upside down. Am I right in this assessment? Please feel free to comment on technical issues you see with this vault I will try to upload video. More descriptive comments the better. Looking for directions, drills, etc to help this young man. Sectionals is next week.
Thank you
Vault 1: http://www.youtube.com/watch?v=R6DpIEDkI_0&feature=youtu.be


Vault 2:http://www.youtube.com/watch?v=AL0Cs69pCRk&feature=youtu.be