I tryied to convert my avchd files to SD mpeg2 (avchd editing was not possible on my old workstation ... a dual 3GHz Xeon) and edit the entire project.
Then I used a text editor to replace all the .mpg occurences with the full resolution .mts filenames (the same for all extra application generated files) .....
It was a tedious procedure but it works (you have to change the project settings after file swap ;) )
Now i could import the project and finishing the export using my new i7 WorkStation :D