Looks like you should be able to dial a *27 and turn the OBiWiFi adapter into an access point as opposed to a client.
Rather strange to put a config like that as a star code instead of with the other config options under *** (aa2).
I don't have the OBiWiFi (silly price for a weak wifi dongle) or I'd try it...
If you do not like it being *27 you should be able to change it in the star codes profile (A or B) for the respective phone port.