Dex or dex converted consoles cannot playback DVD or BD movies. Two technical limitations exist. First Official DEX firmware lack some components to playback movies. Second the console type setting that is changed to make a console a dex also controls the playback region. So a console cannot be a DEX console and a north american retail console at the same time for example.
As far as the disc burning goes you can burn discs using the software and it will work the same as using the BD-EMU. That means you need a game update installed on the PS3 hard drive or a true debug self (or EBOOT.BIN) on the disc to run. Currently the tools to decrypt selfs aren't complete in the decryption of the .ELF section headers.