PGP SSO for WDE and not for Removable

Good afternoon everyone; 

Could somebody help me to solve the problem below?

When I encrypt a removable disk with Single Sign On functionality enabled "encryption of disks to existing Windows Single Sign-On password" the PGP encrypts removable disk using domain password of the user and never ask about any password.

I have a customer who wants to encrypt hard drives using SSO and domain password and removable disks with a user password which is typed before the encryption.

Does anyone know how to turn off the option to encrypt removable disk with domain passwords without lose the SSO functionally to WDE and Hard disks?

Tanks in advance