It doesn't work for every game. In order for it to work, you need the pad address that the game places controller info on at minimum. SSBM has already been identified to not use a pad address, too, meaning you have to use the scripts.
Because I do not own a copy of SSBM 1.0 I cannot play that online. However, Penopat and I have tested SA2B to work (almost) perfectly, even in stages that aren't normally available in 2P (*cough* we successfully raced through Green Hill). The problem was, he was recieving my pad address info, but I was not recieving his. We haven't been able to find the issue. The scripts handled the movement instead (X, Y, Z positions are part of the script).