Hi Peter,
you can set the PartNumber, Description and other CustomData related to the IC-Mechanical elements,
editing the file IPRO_BOM.ini.
This file is placed in the ..\Norme\"NormativeName"
So, as example, if you want tho set the elements related to DIN normative, you have to get the file in the ..\Norme\DIN\ folder.
Every normative available in IC-Mechanical (UNI-DIN-ANSI) contains an IPRO_BOM.ini file.
You can edit it using a text editor.
The syntax used inside this file is very simple and it's explained in the header of the file.
I hope this can help you.
Maurizio