Making Real Names of users visible to everyone in the community?

My Buddypress installation has a number of profile fields, including the default "Give Name" and one I created called "Surname". I auto-enroll via upload users only with their usernames and passwords, so they must go in on their own and fill in the other details of their Profile.

By default, all the users see each others' usernames (a combo of their givenname+surname), but if a user goes in and adds details to their profile -- for instance writes in their Given Name and Surname, then all the users start to *only* see the Given Name. Do you follow what I'm saying? I want to find a way to show both the Given Name and the Surname.

For example, after I upload a member named Mr. John T. Smith, his handle will be seen by others users as "johnsmith". After the user completes his profile details, other users will only see "John". But my goal is to show them all "John Smith".

I have a Buddypress installation already with about 700 members and it's pretty active, so I do not want to mess up too much with their fields or cause problems.

I found this "BuddyPress Real Names" plugin, but I'm not sure it will do what I need it to do and I'm worried if I install and rebuild my fields I will create problems. Does anyone have any ideas or suggestions?