Hello!
I can only suggest that you try Vienna Ensemble with Sibelius. That's what I'm doing these days. Actually, I'm using VE Pro. If you use VE Server with Sibelius, you'll have a nice mixer, and you can load your Reverb into a Bus channel right in VE. There is a good 'how to' in your user area for working with VE and Sibelius.
I don't know what Reverb you want to use, but just be aware that you'll need the 64bit version if you're using 64 bit VE. Otherwise, you can run the 32 bit version of VE to load a 32 bit Reverb.