I'm blind just like you, and I've used Aria Player before. I have JAWS 15. You can access the submenus of instruments if you switch to the JAWS cursor, then press Control plus the Left and Right arrow keys until you hear "Empty". Then you route the JAWS cursor to the PC cursor by pressing JAWS key + Numpad Plus, which sort of simulates a right-single-click. Then you can press the Arrow keys until you hear "Import". This opens a dialog box where you can browse for the instrument you want to load up. You can also use this method to activate your instrument, simply by going to the folder where you saved your activation key and pressing enter to open it. I did that with both Jazz and Big Band 3 and Garritan Classic Pipe Organs, with successful results! Which functions are you trying to access? Are you trying to get to the functions that control effects like rotary speakers, chorus, and reverb? I myself am trying to access those, but I don't know where to start.

I will try that out, as changing instruments after selecting my first one, is the main challenge. I can use the menu to change my sound card and midi settings, so it would be good if other primary functions were also put in to the menu as well. but a more accessible tree view, like that found in Windows Explorerr and other file based aplications would be good.