I'm afraid only PIN. But to catch it just decrease the 8th digit by 1 and run reaver manually from command-line, it will try it and retrieve the password for you (alternatively connect to the WPS-advertised variant with the PIN and fish for the password where they are stored on maemo, can't remember atm, quick search should help)

Edit: found it, just run this after one successful connection with PIN:
gconftool-2 -R /system/osso/connectivity/IAP