I would start by making sure both the SA520W and the AP541N is running latest firmware. Seems as if you do have SA configured correctly and AP541N; please verify your firmware is updated and if you still having trouble give Cisco SBSC a call @ 1-866-606-1866 and open a support case.
Article ID:5727 Configure the Single Point Setup on the WAP581 Objective
A Wireless Access Point (WAP) connects to a router and serves as a node
to the Wireless Local Area Network (WLAN). Clustering is when multiple
WAPs are joined on the same network. Th...
Article ID:5706 Upgrade the Firmware on the WAP125 Objective New
firmware releases are improvements from previous firmware versions.
Network device performance can be enhanced when an upgrade is made.
Firmware files can be downloaded through: Trivial File...
Article ID:1972 Configure Time Settings on a Wireless Access Point
Objective The system clock provides a network-synchronized time-stamping
service for software events such as message logs. Without synchronized
time, accurate correlation of log files betw...