You want to send it the following message:
SYSEX_OPEN EVENTIDE H4000 id message_code <lots-o-bytes> SYSEX_CLOSE
where (0x means hex):
EVENTIDE is 0x1C
H4000 is 0x70
SYSEX_OPEN is 0xF0
SYSEX_CLOSE is 0xF7
id is 0
message_code is SYSEXC_USEROBJECT_SHORT = 0x3c
<lots-o-bytes> is "25d <num>" this is a text string
where <num> is 0 – XMT, 1 – THRU, etc.
So, for example, to set output mode to THRU, you would send (all hex bytes)
F0 1C 70 0 3C 32 35 64 20 31 F7
It will reply with a similar message, but message_code will be SYSEXC_VALUE_DUMP (0x2E)
Let me know if it works for you
