According to what I have read, it seems that CAPICOM does not support the verification of PKCS#7 that do not contain the signer's certificate, while, on the other hand, PKCS#7 can come without the signer's certificate!
In other words, it seems that the CAPICOM API does not allow you to explicitly specify the signer's certificate/public key.
I am looking for a possible/easy way to "inject" the signer's certificate into the PKCS#7-without-signer-certificate in order to get a PKCS#7-with-signer-certificate that I could use with CAPICOM?