Help me to import my secret key please

[Stephane Dupuis]

Hi everybody.

After a install "from scratch" of my computer (ubuntu 10.04), I try to
import my previous secret key.

Don't ask me why, but I did'nt save the .gnupg directory.
Instead, I have a .p12 file with the secret key inside.

After lots of try and read on the net, (thanks google) I manage
to import this file with gpgsm :

$ gpgsm -K
gpgsm[5195]: can't connect to `/home/hoper/.gnupg/S.gpg-agent': Aucun
fichier ou dossier de ce type
/home/hoper/.gnupg/pubring.kbx
------------------------------
           ID: 0xFFFFFFFFC8ACF3C4
          S/N: 01
       Issuer: /CN=xxxxxx /L=78210/C=FR/EMail=xxxxxxxx
          aka: xxxxxxx
      Subject: /CN=xxxxxx /L=78210/C=FR/EMail=xxxxxxxx
          aka: xxxxxxx
     validity: 2009-06-09 19:48:13 through 2011-08-18 19:48:13
     key type: 4096 bit RSA
    key usage: digitalSignature keyEncipherment
  fingerprint:
A5:75:99:1E:F7:71:71:6C:AE:43:93:9F:23:00:6F:BD:C8:AC:F3:C4

and this file :
/home/hoper/.gnupg/private-keys-v1.d/F3FFEFBE7661DDAC15F5B1625F9168AF818E8396.key
was created. 

But I want this key to be used as my "default secret key". Well, I want
it to appear in the output of "gpg -K". 

How can I do this ? 

btw, I already manage to import the public key :

$ gpg --list-keys
/home/hoper/.gnupg/pubring.gpg
------------------------------
pub   1024D/1F03B55A 2009-06-09
uid                  hoper <xxxxxxxxxxxx>
sub   4096g/F7C66E72 2009-06-09

My only problem is with the secret part. (my secring.gpg file is still
empty). 

Any help will be really appreciated...
(and for people who can speak french, you can answer me here:
http://forum.ubuntu-fr.org/viewtopic.php?id=395363 )

Thanks !