Simples Assim

import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.component.http.HttpMethods;
import org.apache.camel.component.http.HttpProducer;

public final class SampleRouteBuilder extends RouteBuilder {

  @Override
  public void configure() throws Exception {
    from(...).setHeader(HttpMethods.HTTP_METHOD, HttpMethods.GET).setHeader(HttpProducer.HTTP_URI, "http://www.fernandoribeiro.eti.br").to("http://host");
  }

}

http://camel.apache.org/http.html