Currently it is not possible to authenticate at Symantec Drive Encryption's Pre-Boot authentication screen, called Bootguard, using the HP Envy virtual keyboard. There is a formal request to add virtual keyboard support at Bootguard for for HP Envy.
Attached keyboards are still fully supported on these systems and only virtual keyboards are not currently supported for this hardware.
Technical Support filed a Feature Request to add this product feature. Note that an feature request is exactly that, a request. There is no committed date for this request from the Endpoint Encryption Product Management team, nor from the Endpoint Encryption Engineering team at this time.
Please be sure to refer back to this document periodically as any changes to the status of the request will be reflected here.