storing ldap passwords on HSM

Greetings, I have been searching webpages for guidance on using a smartcard ( also know as an HSM ) for storing passwords for an ldap database on a linux system. This would include for instance how would the userPassword (attrribute) be specified - i.e. how to specify the userPassword to read the PIN/SO- PIN/PUK{whatever} of the HSM/smart-card etc etc ?? Any guidance would be much appreciated. Yours sincerely luxInteg