Mixdown not showing up in Final Cut Pro

I really like Soundtrack Pro, but I am so frustrated. I have an 11 min sequence in FCP with 2 mono tracks and a stereo track. I sent to STP multi track, added some sound effects etc. and then Exported the Master Mix back to Final Cut Pro.

When FCP opens, all the audio tracks are ghosted (grayed) and the clips in the audio are the same ones that are exported... rather than being 6 aiff files.

Has anyone else had this problem? What could I be missing.