Connector.open throws IO when using 3g

I'm using the javax microedition Connector class to initialise a HttpConnection. This doesn't work with 3g while it works with wifi.

HttpConnection connection = (HttpConnection) Connector.open("http://ww开发者_开发知识库w.google.com",Connector.READ);

I'm trying to solve this by detecting 3g. Can this be done?