Can't transfer old secret subkey to 1.0.7 secring

[Volker Gaibler]

Hello everybody,

switching to GnuPG 1.0.7 I tried to copy my old encryption subkey (from
old 1.0.6 secring) to my new secret keyring. 
Until now I have used the old subkey by using an additional secring in
the options file.

secring.gpg
-------------------------------
sec  1024D/86ECAC0B 2001-12-05 Volker Gaibler <mail@volker-gaibler.de>
ssb  2048g/B5AAC15E 2002-04-02

secold.gpg
------------------------------
sec  1024D/86ECAC0B 2001-12-05 Volker Gaibler <mail@volker-gaibler.de>
ssb  1024g/490CC343 2001-12-05

When I now export the old subkey 490CC343 via
gpg -a -o secold.asc --export-secret-keys --secret-keyring secold.gpg 490CC343

and import it to the new secring via
gpg --verbose --import secold.asc

I get the error message
gpg: armor header: Version: GnuPG v1.0.7 (GNU/Linux)
gpg: sec  1024D/86ECAC0B 2001-12-05   Volker Gaibler <mail@volker-gaibler.de>
gpg: key 86ECAC0B: already in secret keyring
gpg: Total number processed: 1
gpg:       secret keys read: 1
gpg:  secret keys unchanged: 1

The same happens when exporting with --export-secret-subkey
Shouldn't the subkey be added to my new secret keyring?
Or is there any other way to copy the old subkey to the new keyring?

I found a quite similar question by Frank Ollig (Wed, 24 Apr 2002) but 
no answer to this in the list.

Volker


-- 
 Volker Gaibler                                 contact:
 http://www.volker-gaibler.de                   mail@volker-gaibler.de
 OpenPGP key: 0x86ECAC0B
 get my public key from website above 
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