This post was over a year ago. I have the same problem. Did you ever figure it out?
I was asking the question prior purchasing the WU-1A. I took the plunge anyway and bought the adaptor. I never connected to the MBP or Lightroom. I did however connect to my iPad with the "WMU" app downloaded from the app store. I found the adaptor of limited use generally. I like having it for those situations where I cannot use the viewfinder, the live view works well. I had my camera on the floor shooting straight up and the WU-1a was great to frame the shot and focus using the iPad. It is a battery hog so watch how long you leave it on.
Have a great day, Rick.