Just an update about DWG exporting - based on http://help.ptc.com/creo_hc/creo30_pma_hc/usascii/index.html#page/pma/data_exchange/About_Importing_DXF_or_DWG_Drawing_Files.html where PTC states
"Note: The PTC Creo Parametric Interface for DWG uses RealDWG technology."
The Help link is incorrect - at least it doesn't lead to RealDWG. This is a current Autodesk link http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=770257 to the Autodesk Developer Network page.
It supports "read and write support for AutoCAD releases since AutoCAD Release 14"
It's available through TechSoft, the company that also handles HOOPS and Parasolids.
An interesting interview with the top guy at TechSoft http://www.deelip.com/?p=3501 indicates that HOOPS was used in eDrawings and CADDS 5.