I have tried with various methods but none seems to keep scale, material attributes and textures. Don't know if Archicad will do it, but 3ds is a good format for keeping textures in order.
Scale is no trouble either.
The FACT file format does support textures and if version 6.0 of ArchiCAD can export the FACT file format we would like you to send us a file so we can investigate why this will not import.