WL-500gP - Wireless Security and HDD

I bought one of these routers to replace my old Linksys BEFW11S4. There was a compelling reason for that: my new laptop, a Toshiba with Intel 3495ABG card, could not connect to the Linksys in wireless mode.

At home all my 3 computers use Windows XP and have different wireless cards (Intel 3496ABG, Intel 2200BG, and Surecom USB 54M dongle).

There are two interesting features of the WL-500gP that I would like to exploit:

Wireless Security
The "purists" claim that WPA-PSK is far better than WEP-128. One month ago I've tried to use WPA-PSK. At the time I was using ASUS fw 1.9.7.0 with external disk and Samba enabled. The WPA-PSK protection worked with the Intel cards (I could not test it with the Surecom dongle), but router stability was not satisfactory. I had to reboot it very often. Now I am using Oleg's 7F fw. I am using WEP-128 + hidden SSID + restricted MAC access and all is OK. Is Oleg's support for WPA-PSK stable, and if yes, is it worth the move from WEP-128 to WPA-PSK ?

USB external disk
This router is very stable (in fact, much more stable than the Linksys BEFW11S4 ever was), except when I connect an external disk, in my case an IBM 40Gb portable USB2 disk (recognized by the drivers as a Fujitsu device).

After numerous tests it all came down to Samba. With the version included in Oleg's 7F fw, whenever a laptop had a power off/on (or hibernate / resume) cycle, I had to reboot the router to allow the laptop to access the router again. Disabling Samba solved the problem. But now I have another problem: how to access the disk attached to the ASUS from my Windows XP computers ? Apparently I have 3 alternatives:

1) Updating Samba to V3 (IPKG version): I've tried this, but gives an invalid system call when I launch smbd (nmbd starts ok)

2) Installing vsftpd. I'm trying this, but I don't know how to setup it for non WAN access, LAN access open for guests / anonymous but restricted to a certain folder and its subfolders (when I say open I mean read / write / delete files and folders)

3) Enable NFS in the router and install NFS clients on all 3 Windows machines

I would like to know what is the more stable alternative, and how to set it up.

Thanks a lot,