so i am stuck with the Canon power adapter.
maybe not. i'm trying to build power adapter myself, based on standard atx power supply from PC.
i'll let you know if that works. keep in mind that power supplies such as ATX already have a set of currents such as 3V, 5V, and so on, so i'm going to use it as a power source for both my A550 (3.15V, 1A) and S3 (7.4V, 2A).
either way, i'm not going to pay canon huge amount of $$$ for such a simple device