After my latest replacement we noticed that my WAP4410N was a first generation version, having some problems with gigabit ethernet connections. After contacting Cisco we found out that the version should be replaced by a v2 instead.
Some difficulties with the replacement procedure (follow this, get a different ticket within the box, needing to get the arrangement with the carrier yourself) etc. I am now running on a fine working (so far at least) version2 WAP4410N.
Hurray for Cisco for their continued support!