Aras 9.3 Cannot identify the UG NX prt filetype properly

Hello, everyone:

I found that the UG NX's prt file is not in the Administration/FileTypes list, and I tried to add an item for this filetype. As the UG NX's prt file has the same extension as the ProE Assembly does, I changed the ProE Assembly's extension field to "prt_disable". But, when I uploaded a UG file, it still shows that it is a ProE Assembly file. 

Does anyone has some ideas about how to let the Aras identifies the UG file properly?

Thanks,

Will Wang