How to remap a midi controller?

But to answer your question more directly. Take a look at this script:

//Check if we're receiving a CC1 on channel 1:
if (event.trigger.midiBytes[0] == 0xB0 && event.trigger.midiBytes[1] == 1) {
    //Send out a CC2 on SoundFlow Custom Midi Output 1
    sf.midi.send({
        midiBytes: [0xB0, 2, event.trigger.midiBytes[2]],
        outputNum: 1
    });
} else {
    //Pass the message through
    sf.midi.send({
        midiBytes: event.trigger.midiBytes,
        outputNum: 1
    });
}

In the first if line, the == 1 is the CC1, and in the following [0xB0, 2, ...] the 2 is the CC2 that it is being directed to.

If you want to do CC1 -> CC101 and CC2 -> CC102 you'll need to have another if/else section, as such:

//Check if we're receiving a CC1 on channel 1:
if (event.trigger.midiBytes[0] == 0xB0 && event.trigger.midiBytes[1] == 1) {
    //We received a CC1 (== 1) on channel 1 (0xB0)
    //Send out a CC101 on SoundFlow Custom Midi Output 1
    sf.midi.send({
        midiBytes: [0xB0, 101, event.trigger.midiBytes[2]],
        outputNum: 1
    });
} else if (event.trigger.midiBytes[0] == 0xB0 && event.trigger.midiBytes[1] == 2) {
    //We received a CC2 (== 2) on channel 1 (0xB0)
    //Send out a CC102 on SoundFlow Custom Midi Output 1
    sf.midi.send({
        midiBytes: [0xB0, 102, event.trigger.midiBytes[2]],
        outputNum: 1
    });
} else {
    //Pass the message through
    sf.midi.send({
        midiBytes: event.trigger.midiBytes,
        outputNum: 1
    });
}