I've never tried adding attachments from the library. I'm somewhat confident you can do what you're asking via SQL by adding records to tables per attachment. Have two sessions of Maximo up. You turn on SQL logging to INFO just before you perform your action, perform your action on the other tab, then turn of SQL logging back to WARN. You'll see the SQL involved with attaching from library. The SQL straightforward although you'd have to use sequence.nextval for the insert ID.
The safer and supported way is to load attachments with MxLoader 7.52. I put a comment with the specifications in the link below: https://bportaluri.com/2017/06/mxloader-attachments-doclinks.html
If you upload again, you'd duplicate the attachments and take up extra disk space, but again, that is the safer way without having to interact with the database directly...
#SupportMigration#AssetandFacilitiesManagement#Support#Maximo