WEP Key Management

I've got a small home network consisting of the following;

Netgear Acceess Point WG602 - WEP only
Netgear PCI Card WG511
Linksys WUSB 11 11b
Dell True Mobile handheld.

I've entered 4 x44/64 bit keys into each and have the AP's default key
as Key 1.

Now have I got this wrong!! Reading the AP's help file it states that
the default key is used for transmission only and the others for
received data so I understand this to mean that the adapter cards can
use any of the four keys to transmit but naturally need the AP's
default key to receive the data.

At the moment I can ony get my network to function if all units use
the default Key1, if this is the case what is the use of having four
keys.

Geoff Lane