When i set up "2,4 B/G" mode on RB433 or 433AH client's cards in B mode can't connect to AP. In "2,4 B" it works fine. My friend has the same proble with RB133 and Wistron CM9 mPci card as AP.
In manual I've read:
"• 2.4ghz-b/g - IEEE 802.11g (supports also legacy IEEE 802.11b protocol)"
i think, that IEEE 802.11b protocol isn't supported.