routing slip with InOut pattern

[Tim Dudgeon]

Is is possible to use routing slip so that it always waits for response?
For instance if the routing slip specifies a seda route then it seems to 
execute asynchronously and the routing slip returns immediately.
If instead I route to a direct endpoint it waits as desired, but that 
direct route is blocked and won't take any more messages until complete.
For example:
from("seda:start")
  .routingSlip(header("someHeader")
  .log("routing finished");

from("direct:routeA")
   .delay(5000)
  .log("hello from route A");

from("seda:routeB")
  .delay(5000)
  .log("hello from route B");


I want to send message to seda:start with routing slip header that 
specifies seda:routeB but I want to see "hello from route B" before I 
see "routing finished".

Thanks
Tim