NSS get revocation date of a certifacte

Hi, I'm trying to get the revocation date of a certificate but cant find a easy way to do it.

I have finded "CERT_PKIXVerifyCert" which tells you the status of a certificate, in the case of a revoked certificate it will tell you with a status that the certificate its revoked. 

But I need to get the date of revocation of a certificate to compare it with the date of signing of a pdf file (a digitaly signed file).

Are there a function that allows me to get the date of revocation of a certificate? I searched a lot, but cant find anything.

Thanks!