Hi Tomomi,
First, what version of ACM are you using? I use 10/10.1. When I create and upload a DITA map, I see the title of the topicref. When you burst a standalone procedure, is it saving as the title name, the document number or other? The title name of the files can be modified within your bursting config file.
Also, when you go to the details page of a DITA map, go to the Structure tab. Here you'll see a sub tab called "Uses." This will show all of the files referenced by that map. It will display them by the filename stored in Windchill. If this shows the document number as the file name, then I would check your bursting config file for what it is using to set the filename.