Not what you were specifically asking about, but just for the sake of comparison (or if someone else is considering what I did)....

I use a Zyxel USG40 router and just added a pair of Zyxel NWA5123-AC access points (for a bunch of wireless stuff in the house, including 3 TSU9600's). The router and AP's recognize each other, so the router does all the management of the AP's directly (the AP's can be managed via a web interface if you don't have a router that can manage them).

Each AP has 2.4GHz and 5GHz radios, and can support a number of SSIDs. I have an SSID configured for WEP that works nicely with the TSU9600s (so far -- I've actually only had it installed for 2 days, now -- same thought as you about updating, Barry :-). I also have it doing MAC address filtering for a bit of extra security. If you use one of these, the settings that I found work are:
Security mode: wep
MAC Authentication: unchecked
802.1X: unchecked
Authentication type: open
Key length: WEP-128
Key: the 26-digit Hex representation of the WEP Passphrase