Using ldap in Thunderbird to retrieve userCertificate attribute from the strongAuthenticationUser object class?

If this is the wrong group please let me know:

Using ldap in  Thunderbird to retrieve userCertificate attribute from
the strongAuthenticationUser object class?

I want to retrieve a recipients email certificate. From what I have
been able to find on the internet I need retrieve the attribute
userCertificate from the object class strongAuthenticationUser. Where
do I specify the search filter to retrieve the userCertificate;binary
from the object class strongAuthenticationUser in Thunderbird?
thank you
jockey