Hey Jayson,
You can do that by writing an ABAP program.
Comment table follows a fixed naming convention. BPC automatically creates tables /1CPMB/XXYYYCMT and /1CPMB/XXYYYCMTA to store comments in SAP.
In order to see the comments table, you need Appset prefix(XX) and Application prefix(YYY), which you can get from tables like UJA_APPSET_INFO and UJA_APPL.
If you want to follow an easy approach try to debug class CL_UJC_CMTMANAGER and use method cl_ujc_cmt_dao->ADD_CMT().
Let me know if it worked.
Thanks,
Deepanshu