Outlook 2007 + external CSP: unknown error
 

We are using MS Outlook as main mail client for secure mail exchange. Message
encryption \ digital signing is done using external CSP (cryptographic
service provider) Crypto-Pro 2.0. At first we used Outlook Express, then
switched to 2003.

Everything was OK - we set up certificates for DS & encryption in
Parameters-Security, imported certificates for contacts we wish to have
secure exchange with. Outlook 2003 signed and DEcrypted messages, but when
trying to ENcrypt message we got error "Messaging interface has returned
unknown error" or, in rare cases, "Some parameters were not set". This
problem was fixed with SP2 for MS Office 2003, although i still dont know
which reason caused it.

Now we started moving to Office 2007, and guess what? Same story - setting
cert-s in Trust center, importing in contacts, signing okay, decryption okay,
but when trying to encrypt - "Messaging interface returned unknown error"
(tried 2 CSPs: Crypto-pro 2.0 and eToken Base CSP, same thing). Is there any
workaround for the problem or we have to wait for patch/fix by MS?