Can't create a second version of a shared transport channel

SharedTransportTest.testReCreationWithSurvivingChannel() shows the problem:

// Create 2 channels sharing a transport
a=createSharedChannel(SINGLETON_1);
a.connect("A");
b=createSharedChannel(SINGLETON_1);
b.connect("B");

a.disconnect();

// a is disconnected so we should be able to create a new
// channel with group "A"
c=createSharedChannel(SINGLETON_1);
c.connect("A");

This is basically testing a scenario where a service that creates/connects a channel is restarted.

This works fine if the 'b' channel isn't connected. AFAICT, problem is Configurator.startProtocolStack() is storing data in the TP.up_prots map, but the disconnect() process (e.g. Configurator.stopProtocolStack()) isn't removing it.