Its not impossible, the BSQ is many Seq's stuck together, you need to pull them apart properly.
Edit: Btw if you google the PS1 dev kit called "PSYQ" you'll find the real smf2mid by s0ny
(smf is simple midi file..)
Edit again: It would actually be very handy to know if they're unmodified SEQ files in the PC version, if you can't find the tool I may give you directions on how to... "obtain" it if you'd like