@Steve Sommers:
The code will be dynamic based on the URLs that are stored in the content - which we won't know until the content has been entered, and even then the content will change every week so any method that involves manually importing certificates will not be possible - it's meant to be an automatic thing, so I think that from this and the other Google searches I've done, it's not possible in CF.
@REEDPOWELL:
I will look into the curl method, if this is able to do what I need and I can trigger it and get a response within CF then it looks (so far) like the only solution. I had already found that post by Ray Camden, but it gave the same dump with the I/O Exception, so it didn't work for me.