Problems with interpolibility between GnuPG and PGP when using SHA384-SHA512 hashes

[Joe Vender]

Is there some internal incompatibility between the SHA512 and SHA384 
hashs in GnuPG and the same hashes in the new  PGP sdk 3.x of PGP 8.x? 
According to information at http://www.pgp.com/products/sdk.html , the 
new PGP sdk 3.x supports the large hash functions including SHA256, 
SHA384 and SHA512. However, when I sign a message in GnuPG 1.2.5rc2 
(with SHA512 compiled read/write for testing) using SHA512 as the hash, 
PGP returns "BAD Signature" when verifying. Same with SHA384 signed 
GnuPG messages. PGP *DOES* verify signatures correctly when GnuPG uses 
SHA256 as the hash. Any idea what the problem might be?

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PGP Encrypted/Signed Email Preferred
See the kludge (full email headers) for my PGP key