I don't understand Your question. X360 saves and PS3 saves have different meta data structure. If this PC application (?) doesn't support PS3 saves, You need disguise it as X360 save. But that's depend how the app was written. I don't saw it and I don't learning in memory every apps GUIs... Maybe attach some screenshots and attach readme for this app, so we can put some ideas based on.
BTW: Save decryption can be made by Apollo Save Data Tool (PS3 side) or Bruteforce Save Data (Windows; You need Yours IDPS to do this).