Using two internet conections simutaniously

[cmosdsnr]

I use two DSL lines. Often utorrent works fine and uses both connections to download, double rate. Sometimes it seems to forget there are two and use only 1. If I disable the one it's using in device manager (disabling the network card) it "remembers" the other one and starts using it. Turn the original one back on and it starts using both again.

Anyone have any idea what's going on?

This happens frequently. It's always a specific conection that it is "forgetting". The "forgotten" conection is fine, I have internet access thru it.