Changing default digest algo

[Chuck Peters]

I generated some new keys in Sept and would like to convert the digest
from SHA1 to SHA512.

I added the following to gpg.conf:
personal-digest-preferences SHA512
cert-digest-algo SHA512
default-preference-list SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES
CAST5 ZLIB BZIP2 ZIP Uncompressed

I changed the preferences:
gpg> setpref SHA512 SHA384 SHA256 SHA224 AES256 AES192 AES CAST5 ZLIB
BZIP2 ZIP Uncompressed
 
And verified:
gpg> showpref
[ultimate] (1). Charles F. Peters II (Chuck) <cp at axs.org>
     Cipher: AES256, AES192, AES, CAST5, 3DES
     Digest: SHA512, SHA384, SHA256, SHA224, SHA1
     Compression: ZLIB, BZIP2, ZIP, Uncompressed
     Features: MDC, Keyserver no-modify

When I check the keys, it still shows SHA1:
$ gpg --export-options export-minimal --export 23E9EB24 | gpg
--list-packets |grep -A 2 signature|grep 'digest algo 2,'
        digest algo 2, begin of digest a3 6e
        digest algo 2, begin of digest 3b 34
        digest algo 2, begin of digest f2 3e
        digest algo 2, begin of digest ae 58
        digest algo 2, begin of digest 67 fa
        digest algo 2, begin of digest e6 39

I tried a few things like changing the passphrase, signing my key and
gpg --s2k-digest-algo SHA512 --edit-key 23E9EB24 and nothing seems to
work.  How do I change the digest to SHA512?


Thanks,
Chuck

1. http://www.debian-administration.org/users/dkg/weblog/48
2, https://we.riseup.net/riseuplabs+paow/openpgp-best-practices