The 720 DOES have this feature. Orifginally, the NA model was not supposed to have it, just the European model.
But about 18 months ago, it was discovered that a combination of: Navcore 7.481 or higher plus NA map 7.10 or higher plus (and this is the 'hack') a text file called support_asr.dat with just a 1 in it, no blanks or anything and this file goes in the asr folder.
All that plus the existence of cspeechxx.dat files in NA map 7.10 or higher will allow for the VR.
As a matter of fact, for a time, later NA models were indeed shipped without the support file and VR still worked.
TT said it was a mistake. Those units were meant for Europe only.
Well, bottom line: if you have the speech files in the NA map you have and the support_asr.dat text file in the asr folder, you will have VR.