In our process we have 2 steps that we need to address. We have to manage digital signatures in server side (ASP.NET) and in Client Side, but in server side is the major problem for us, because we need to have MSWord installed on the server to work with digitalsignatures.
So in server side, when a user upload of a word file we need to now how much digital signatures the word document have and the information about the last certificate to indicate in our application the user who signed the document.
In client side, we need to sign the document with a digital signature installed in client machine. Most of our users have MSword installed in their machines and we open the doc with Office PIA to sign the document.
The server side is our major problem because we can have the MSWord installed in server.