The solution was use the same linux command in windows, and it works like a cham.
plesk bin subscription_settings --update DomainName -mail_certificate 'certificate_name'
I need to add a mail certificate to a subscription.
We have found this undocumented command that works fo linux
"plesk bin subscription_settings --update DomainName -mail_certificate 'certificate_name'"
in one of the plesk forums, but we can't find how to do it on windows, we have tried this...