I don't know if you can do this with Basic or not, as I'm running Enterprise, but here's where you can do it for Enterprise.
1/ Trap definition: Go to Alarm -> Trap Management -> Trap Definition. Near the top of the page is an option "Import trap definition from MIB file". That lets you define new traps from a MIB file.
2/ System -> Resource Management -> MIB Management. From the pop-up, go to Tools -> Load MIB files to load new MIB files. This one is for use with the MIB browser, and to help with adding new customer monitoring settings.
Can you check those locations, and see if you have those options?
(NB In spite of what many people think, just loading MIB files does not magically add device support for new devices).