The easy answer to this may be to do it in steps rather than directly. Concept here is that you would map the attributes between the CAD Tool (Parameter) to the CAD Document and then CAD Document to WTPart.
The Parameter (in Creo) to use is PTC_WM_NUMBER. Similarly you can do the same with PTC_WM_NAME... although recall tells me for some reason this is PTC_COMMON_NAME is Creo.