I have a network composed of cable modem to Airport Extreme for routing and WIFI and an
Airport Express extending the WIFI, as well as driving a pair of speakers.
The network recently changed from the Extreme in bridge mode connected through a
switch to a Motorola gateway which provided cable modem and router services.

At the time of the change, I used Airport Utility to change the Extreme to router mode and
provide DHCP and DNS pointers. That worked well and the network works very well.

The single exception was the Airport Express used for extending Airplay to a set of
powered speakers. That previously had worked well, and now works OK if I go into
system preferences and set the output to the AE speakers.

However, the Airport icon in the activity does not list the set of speakers attached to the
AE, and I am unable to find any Airplay Icon in ITunes.

I would appreciate any help to tell me what I did wrong, or what I missed.

I have completely reconfigured the AE from a factory settings reset,
and everything seems to work except the Airplay.