If I go to the outlook browser app and download an S/MIME signed / encrypted mail from there I get this file:
Running mimetreeparser-widgets on it results in:
./mimetreeparser-widgets /tmp/S_MIME\ s_e\ with\ attachment.eml 13:41:32.307 org.kde.pim.mimetreeparser.core: MimeTreeParser::ApplicationPkcs7MimeBodyPartFormatter::process pkcs7 mime == S/MIME TYPE: enveloped (encrypted) data 13:41:32.307 MessageParser::setMessage Message parsing took: 0 13:41:32.368 Crypto::decryptAndVerify|?libKPim5MimeTreeParserCore.so.5?|?libKPim5MimeTreeParserCore.so.5?|?libKPim5MimeTreeParserCore.so.5?|?libKPim5MimeTreeParserCore.so.5? Failed to decrypt and verify 151011327 13:41:32.369 toResult|Crypto::decryptAndVerify|?libKPim5MimeTreeParserCore.so.5?|?libKPim5MimeTreeParserCore.so.5?|?libKPim5MimeTreeParserCore.so.5? unknown error 151011327 End of file 13:41:32.370 MimeTreeParser::EncryptedMessagePart::decrypt|?libKPim5MimeTreeParserCore.so.5?|?libKPim5MimeTreeParserCore.so.5?|?libKPim5MimeTreeParserCore.so.5?|?libKPim5MimeTreeParserCore.so.5? Failed to decrypt : 151011327 13:41:32.370 MessageParser::setMessage Message parsing and decryption/verification: 63
But If I open It with KMail:
Message should be decryptable with the berta.boss@demo.gnupg.com.p12 key I just sent you