iPhone 3G, iPhone 3GS, iPod touch (2nd generation), and iPod touch (Late 2009) do not support FireWire and will not charge from any FireWire-based power source. If you connect either of these devices to a FireWire-based charger or accessory, you will receive an alert that "Charging is not supported with this accessory." See this:
http://support.apple.com/kb/HT1476
Older accessories used the Firewire pins in the dock connector even though they did not have Firewire, so they won't work.
If your accessory won't charge your iPod Touch, there are adapters available: Here are a couple:
http://store.apple.com/us/product/TV683ZM/A?n=ipodtouch2&fnode=MTY1NDA4NA&mco=MT A4NDYwNDA&s=alpha
http://store.apple.com/us/product/TS696LL/A?n=ipodtouch2&fnode=MTY1NDA4NA&mco=MT A4NDYxMDU&s=alpha