Sibelius 4 and Virtual Drumline make great companions and this is how many of our users work. There are no incompatibilities between the two programs that should worry you. All you need to do to have both programs speak to each other is connect them with a virtual midi cable (free). This process is outlined in an easy-to-follow Quickstart guide that is included with each copy of VDL:2, or can be downloaded anytime from our website. For your convenience, we're including it here (see file below).