I've found a way to bypass the south-west rule in relation to minecart boosters. Here's a pic as proof. If you want to know the say to do it, just read on.
Any crafter worth his salt knows what the south-west rule is and has probably been frustrated by it when building structures like minecart stations and the like. If you don't know what the south-west rule is, take a look here-
http://www.minecraftwiki.net/wiki/South-west_rule
However, I've recently found a simple way to build compact flat resets for minecart boosters regardless of the direction they face. And when I say simple, I mean simple. Just use a redstone torch at the side of the circular track. The circuit will turn the track into the desired shape, and then you can pick the redstone torch back up and go about your day.
If you've found this helpful, then maybe you could give my blog a glance? It's just starting up, but I plan to include lots of minecraft stuff there, like glitches I've found, basic and advanced structures, tutorials, maps, and more. Give it a try if you're interested in advanced minecrafting and the like.
http://minecraftdungeon.blogspot.com/2011/01/first-post-south-west-rule-bypass-found.html