I need to create S/MIME messages using C# (as specified in RFC 2633, "S/MIME Version 3 message specification", and RFC 3335). The only S/MIME library I can find is a commercial library (http://www.example-code.com/csharp/smime.asp), which is no good for us.
Are there any existing libraries to accomplish creating S/MIME messages, and in particular, .p7s files?
I have all the encrypted and signed elements that need to go into this file, but I'd like to create the .p7s file without handrolling my own library with the aid of the RFC document...
EDIT: I've found another commercial S/MIME library, which is still no good for our requirements. It's looking more and more like I'm going to have to hand roll a S/MIME library, which is sad. Is everyone in .net who needs S/MIME using commercial, closed source libraries to do it?