[unexpected signature class 0x00]???

[Maxim Britov]

> > 4. gpg --default-key test --sign test.txt
> >  You need a passphrase to unlock the secret key for
> >  user: "testkey"
> >  1024-bit DSA key, ID C1F67F71, created 2003-03-24

> Here is the problem.  You are signing the file "test.txt", rather than
> signing the key.  You need to use --sign-key rather then --sign.

I know and I think - it must be fix.
When I use pipe - it not worked:
 gpg --export test | gpg --default-key test --sign |gpg --default-key test --import
 You need a passphrase to unlock the secret key for
 user: "testkey"
 1024-bit DSA key, ID C1F67F71, created 2003-03-24
 
 gpg: key C1F67F71: no user ID
 gpg: Total number processed: 1
and when replace --export to --export-secret-key
 gpg: key C1F67F71: already in secret keyring
 gpg: Total number processed: 1
 gpg:       secret keys read: 1
 gpg:  secret keys unchanged: 1

What remove this "Unexpected signature" from keyring?

Sorry my English
--
MaxBritov