There is some difference in the final version of the plugin and the beta version Sibelius has which causes Sib6 not to recognize the VST as ARIA. Therefore, the auto patch load doesn't work. Until they release a patch, you'll have to use manual soundsets.
Don't mind that for now (manual soundset is straight forward to do) but how do you tell Sib to use ModW for volume control instead of CC7. I know you can code values in directly but is there an easier way to it to just use ModW?
I have created a "fixed" XML soundset file that you can select for use with manual soundsets. It's basically the same as the KP2 soundset file without the patch load entries. If you PM me your e-mail, I can send it to you.