Go to her bedroom while she is sleeping, then strip her bra and panties, then a sex option appears (You need "Dream Invader" ability) ^^
Yes but the new scene also req a "Dream Invader" and It should appear after you stripped her. I checked it and everything works fine.
The dream is just a "Dream Invader" button and the new scene appears after you stip her and is "Sex (reg.Dream Invader") button. It's working fine for me and others who played it earlier.