Download by using two internet connection

Hello
I have a weird question, firstly I want to tell you what I did with my laptop

my laptop have two different internet access, one via lan, other via wireless.some time ago when I run Azureus in my laptop and downloading some stuff, I noticed that it's downloading by using both internet connection, with a speed of 2x1Mbit=~2Mbit
OS is in my laptop is Vista.

In my PC there is a different situation, there are alsi two internet connection in it. but a bit different, one via dialup adsl connection other via lan.OS is Windows XP Pro, I tried to do the same thing in my PC but it failed, it only downloads by using only one connection.

Soon, I am not an network expert, is there a way to succeed that, I know LAN Peer Finder plugin but it fails in private torrents and I cdonot have two systems to do that.

What's your idea about this?

tHanks...