Yes seems you are doing it correctly on the gsp, but you have to save on the v3. Looks like you can save up to 100 patches. Make sure gsp and v3 are on the same midi channel.
MIDI PROGRAMMING FEATURES:
The V3 will save the following settings in a MIDI program location
(1 thru 100

a.) The channel selection 1, 2, or 3.
b.) The LOOP1 and LOOP2 on/off settings.
c.) The BOOST on/off setting.
d.) The REVERB on/off setting.
e.) The LED backlight color setting
Volume, tone, and drive mode settings will not be saved.
TO ENTER MIDI / PROGRAM MODE:
1.) Hold down the channel SELECT switch for the channel
setting you wish to save (1,2,or 3).
2.) While holding down the first switch in step 1, press the
other two SELECT switches, and release all three at the same
time. The LOOP1 LED will be flashing.
3.) From your MIDI controller, select (send) the MIDI patch
number you wish to save. The LOOP2 LED will flash once to
confirm. Normal operation is resumed.
To turn the BOOST on before saving the patch, (perform steps
1 and 2 above) then press and release the LOOP 1 switch.
The green BOOST LED will come on. Then perform steps 1-
3 to save patch.