Sign audio driver for public release

Hi all.
My team need to release new audio driver. We have a trouble when signed our driver.
Technical support of my Certificate authority (digicert) said that “They are no longer able to issue certificates for Kernel-Mode Signing”.
I have some question about this:

  1. I cannot sign my new driver by cross-signing or self-sign, am I right ?
  2. The only way to sign my driver is pass all HLK test and submit package to MS
  3. Our project base on simpleaudiosample build on win10. When testing by HLK, process failed at “Audio Codec – Class Driver Audio Logo Test – Certification - Desktop”. Google said that sysvad also fail same case of mine. They said they had to build driver on win7 to pass HCK testing. What should I do? Do I need to rebuild my driver on win7 and setup again testing enviroment ?

This has been discussed here to death, for months. Read the outcome: