My new Alpine car stereo supports MP3 and WAV? formats.
I'm trying to create an MP3 CD to use in it.
The vast majority of my iTunes songs are in AAC format with 1 MP3 song.
The AAC songs seem to require a mixed-format style CD to burn.
Selecting a mixed-mode format CD I have burnt all the songs - only the 1 MP3 song is recognised in the car stereo.
I have Toast 6, Dragon Burn and iTunes (for directly burning playlists).

Is there any way I can convert all my existing songs to MP3 format or burn in MP3 format leaving the songs as AAC? My office dustbin is full of prototype CDs. Toast 6 help menus say to refer to iTunes help, but can't find a specific answer to my dilemma there.

Thank you all for your guidance.