Hi,
The majority of the remaining BASS MIDI EVENTS cannot be converted to a single short Midi message (that I suppose you want to send with the help of midiOutShortMsg WinMM function).
Some of them like MIDI_EVENT_PITCHRANGE require a sequence of short Midi messages (to set RPN 0,0 in this case) or require SysEx messages like MIDI_EVENT_MASTERVOL (SysEx messages can be sent only with midiOutLongMsg WinMM function).
To further complicate things some of the messages like MIDI_EVENT_DRUMS have to be translated to SysEx messages in case of GS mode but can be translated to bank select short messages in case of XG/GM2 mode.
And translating the Reverb and Chorus effect related events requires different SysEx messages in case of GS and XG mode (MIDI_EVENT_REVERB_MACRO, MIDI_EVENT_CHORUS_MACRO, MIDI_EVENT_REVERB_TIME, etc.).
So overall translating the remaining ones are much more complicated than the ready ones and I do not think it's worth the effort.