Here's how I got the Estonian "ID kaart" (smart card for personal identification) running under K-Meleon. Maybe this instruction is helpful for other smart cards as well.
I used the Estonian ID card's Mozilla support version 0.85rc (older versions should be more or less the same but library file names may vary). This is what I did (the smart card should be removed from the slot and K-Meleon and Firefox should be closed in the beginning):
1. Open K-Meleon. Go to Preferences -> Privacy & Security -> Encryption -> Manage Crypto Devices. Delete any appearances of modules with names containing "opensc-pkcs11" (for deletion, select the module and press Unload).
2. Install, if necessary, the smart card drivers. Install support for Mozilla (the latter for Estonian ID card can be downloaded from http://installer.id.ee/media/ID-kaart-firefox.exe). Let the installer configure the support for Firefox if it wants to.
3. Open K-Meleon and go to "Manage Crypto Devices" again.
Press Load and name the new module as
In the lower box, browse to the file C:\Windows\System32\onepin-opensc-pkcs11.dll
("Show hidden files" should be enabled in Windows Explorer to see this file, I think. As for older releases of Estonian ID-card support for Mozilla, I am not sure whether onepin-opensc-pkcs11.dll or opensc-auth-pkcs11.dll should be used. If you cannot find the file onepin-opensc-pkcs11.dll, use opensc-auth-pkcs11.dll). For other smart cards than the Estonian "ID-kaart", the respective smart card support library should be used, I guess.
Then press OK. K-Meleon should say that a new module has been installed.
4. Just in case, restart K-Meleon again. You can now try to login to some site to check whether the ID card works.
5. If you use only one smart card with K-Meleon, you can also go to the address:
(if you do not have that entry, create a string entry with such name)
and change the value to
Now K-Meleon won't ask for the certificate every time and will choose the certificate automatically.
(I do not know what happens as a result of point 5 if you are using several smart cards in the same computer.)
If something goes wrong, just delete the opensc... module in K-Meleon (Manage Cyrpto Devices) with Unload and try again.
Also you can found more info about this in http://ideelabor.ee/ (thanks to andres).