Relinking Audio for Soundmix

Hello, first time poster - maybe some can help:

I shot on RED DRAGON, seperate audiotracks (Zoom F8), but same Timecode.
I transcoded with DaVinci Resolve 12 to Prores 422 for editing and did Autosync via Timecode.

After editing in Resolve I made a "mixdown" (you see from which editing system I migrated
to Prores 422 LT and edited this track into the sequence, so the audio tracks stayed, but the videotracks are gone.

To purpose for me was, that the soundman doesn't have to care about playback settings etc.
He wants to try to mix in resolve 14.

I used the MediaManager to copy the sequence for mix.
I exported an XML auf the timeline for mixing.

I openend a test project and imported the XML, the "mixdown" videotrack is there, but most of the audio is offline.

Maybe there is problem with the Autosync (the audiotracks don't carry the originalfilename anymore, they carry the name of the videotracks)?
Is there a way to Relink the original wave files?
Do I have to make something similar to "commit multicam edits" in avid?

Best wishes and kind regards,
Martin