Pin name is built into the symbol whereas pin nin number is a property that usually gets annotated to the part by some process, placement or back-annotation. It is not possible to fix property locations, all properties can be selelcted and moved. There is a Reposition Properties command to move properties back to the location defined in the symbol - on the context menu of the right mouse button.
P.S. For DxDesigner specific questions post on the 'Ask the DxDesigner Expert' community http://communities.mentor.com/community/pcb/expedition/ask_dxd_expert
Thank you for your reply sir.