You can always have the greeting professionally recorded into a .WAV file, then copy open up SA, create the new Open Greeting, then select the wav file you want. I typically copy the wav file locally on the Unity server (i'm odd, I know). Then go into SA and select the wav file. I just like to keep the WAV files organized on the Unity server in a seperate folder.

The Audio manager is another tool that works also.

Another trick.. you can also export the or "save as" the current Open Greeting or any greeting as a wav file and import it to another greeting. You can really trick someone on April fools and play a good joke on them. Welll.... we wont go there.. but you get the idea or import/export wav files through SA or audio manager

cheers