Have you tried Tools > Assembly Navigator > Export to Spreadsheet? It will kick out the NAV. info to Excel for whatever columns you have active in the NAV. It will insert blank spaces in front of the info in each cell to represent the tree structure.
If you use the BOM in drafting you can export that to excel..
1. create the BOM
2. on the top left corner of the BOM right click and select exprt. This will bring up a dialog box click on file give it a name and location and click apply.
3. Open excel
4. In excel data->import external data->import data-> select the file you created from UG
then you will get a new dialog box that comes up and shows your info before you place it in cells. You can adjust the cell width here to make your data fit in the cells.