Module dont work with feed2.0beta1

Updating Feeds to version 2.0beta1 breaks the existing mapping that links to fields that are not entities.
In fact you can not link a column to a field of a referenced entity anymore.

This is too bad because feeds beta1 solved the export/import problem, and the update from alpha9 has a lot of updates which makes downgrade very complicated.

Did someone managed to deal with this issue ?
Thanks