Where are stored .sav files of Demo Stages?

[Dato24]

I played the episode "Demo Stages" in SMBX2b4.4.1, and I saved with "save and exit". Then, everytime i open the launcher it shows "new file". I thought my progresses were lost. But when i play progresses are restored. Anyway, i cannot delete these progress files until i find them in folders. Where are stored saving files of Demo Stages? Thanks and sorry for bad english

Added in 1 hour 40 minutes 8 seconds:
I solved, the problem was that i installed SMBX in Program Files x86, so without admin permissions the game saves files in appdata instead of data/worlds/WorldName