It works for me regardless of whether I use the CTRL+SHIFT+R shortcut, or Menu > Aircraft > Select Aircraft > press ENTER to reload the same 727. :-/
Once I reload the 727, I have all the sounds working like they should.

It worked this way for me as well. Did the above and have cockpit sounds ( before I started using the 707's sound files to save this step). Never hurts to back track and double check once more to make sure  you did everything mentioned in the knowledge base item. I followed those instructions ( now years ago), did the reload thing, and had cockpits sounds the first time out.
For the money charged for this sim, it ridiculous everyone has to fight this issue and go through this dance. I have to laugh every time CS mentions it will hopefully be fixed soon- now over three years. Perhaps they should reconsider how they respond to customers. Or better yet, just deal with this.