Include full certificate chain up with signtool sign

[Holger Grund]

I'm trying to sign a file with signtool.exe with a PFX file as part of an
automated process. I'd like the signature blob to include the full
certificate chain including the root CA. However, I fail to see a way
to tell signtool. By default it only includes the signer cert and the
intermediate CA.

Any ideas?

Thanks

-hg