Files can be directly uploaded to IBM Connections through the API via a HTTP request. This is documented in the IBM Connections 4.5 API Documentation i.e. when we want to update a file inside Connections we find some informations on how to this here.
Unfortunately the documentation has no examples (as Carl Tyler nicely described in “The Domino Designer documentation team screwed us all“) and is far away from being perfect. Starting point for me was to use the SBT API Explorer on Greenhouse and/or a local Rest client (I’m using the Cocoa Rest client on my OS X machine). Read more