There is an issue with the WAP55AG v2 honoring it's default gateway setting. Linksys 3rd level is already looking into it via ticket: 050528-000784 Since the Linksys website only shows the WAP55AG v1 on their website, looks like I got some of the first Version2 units. Version1 lists the latest firmware version at 1.07.1 . Version2 ( mine ) is at 1.1 .
So for now, you will only be able to manage it via local subnet. So, if you can't "ARP" directly with it, you won't be able to icmp-echo ( ping ) or manage it remotely.
Anyway, just FYI...... ;-)