Sorry for the delay in replying. I needed to have an H8K in front of me.

Your problem is not the Sysex ID – this can be either zero, or whatever your unit is set to.

The reason why this is not working for you is that MIDI messages cannot contain anything which is 80 hex or above (the high bit signifies a command). This is why the document you mention says "With many messages, a "byte" is actually two bytes. Since MIDI allows only 7 bits of data, we split an 8 bit byte into two 4 bit nibbles and send the nibbles. The most significant nibble is sent first."

Note that "nibble" is undefined – if you are not a programmer, you may not know that it is a 4 bit value.

So, the actual message data must be sent as two bytes per byte, with the high 4 bits being zero. The message you are trying to send should be:

F0 1C 70 00 01 0F 0F 0F 0B 0F 0F 0F 0F F7