HP 6980 - won't properly connect "securely" via wireless - only "unsecurely"

Attempted to set up a HP6980 for a neighbour, expecting it to be easy -
connected to a Toshiba laptop via a Draytek 2800G wireless router

But the wireless printing only seems to work when the printer has *no*
encryption set. If the printer has no encryption set, it prints fine.

Setting up using the "manual" option - via Ethernet cable connecting
router to printer - all seems fine... until the Ethernet cable is
removed. At that point, the printer seems unable to find the router
wirelessly - the printer's network indicator light blinks ( indicating
"no connection" ).

It seems that the problem only occurs if the printer is being set to use
encryption. The connection between laptop and router is WEP. If the
printer is set to use WEP it can't find the router, but if the printer
is set to use no encryption it works fine.

( Filtering by MAC address has been set in the router, and that seems to
be fine. )


Any suggestions or comments at this point ? :|