If I understand correctly, you mean enable ASR on the series 7xx as the 8xx?
It is possible?? May be a modding/flashing 7xx model..... I do not know,sorry
Please be aware that, with the latest releases maps (type CNNTEU 2013.30) , the ASR files to the 800 series have been closed. And each map (and series) has its own dedicated ASR files
I know a user (other Forum) with the 865T and LM for EU, and every time he needs to update Garmin is calling for Assistance to be credited with this bouquet of files .... but with the latest release doesnt handle them and are not available anymore. I do not know for CNNA