I changed the file and now I can use two midi files to jump from Voice mode to Multi mode.
I have to ask you one more thing...
Could be possible to add into the file also a bank select + program change commands?
I've tried to add, after the F7 closing of SysEx message this piece of hex
b000 3f (Bank select MSB 63)
b020 00 (Bank select LSB 0)
c058 (Program change 88, the patch is the 89 but it starts from 0)
Of course, it doesn't work...
I attach the file.
Thank you for your kind support