How to add a pkcs#11 interface to seahorse

[François Pérou <francois perou free fr>]

Dear friends,

I am writing a tutorial explaining how to use OpenSSH with smart cards. 
Using OpenSSH / Scp with smart cards / PKCS#11:
http://www.gooze.eu/howto/using-openssh-scp-with-smart-cards-pkcs11

I failed to use ssh-add to inform the ssh-agent of keys on smart card.
I wonder if this is possible to use Seahorse to add a pkcs#11 device.

This is the last page of tutorial and I need help on it:
http://www.gooze.eu/howto/using-openssh-scp-with-smart-cards-pkcs11/using-ssh-authentication-agent-ssh-add-with

What do you think?

Kind regards
François