A while back I experimented with methods for adding banks and SFZ sounds that include UI controls to Aria. This technique is useful for adding SFZ from things like Dimension Pro or SF2 soundfonts that are converted to SFZs, and the tutorial explains how to do both.
This tutorial is a bit long, but detailed and step by step including screen shots. I would be happy to make it shorter or more tailored if there are suggestions.
Hopefully this is helpful.