I too purchased a new HP dv9500T and have had more problems than I imagined with a lot more than just the ExpressCard problem, but I think there is something else to consider. I was going to purchased the Duel Adapter, but I think I am going to have to wait now. Here is some information that may or may not also help. I am also going to write a letter HP and rip them a new you know what for lack of concern. I am a musician using specialized music software programs and audio plugins for recording audio. I first had massive problems getting up and running do to the fact that my FireWire audio interface will not work with the HP dv9500. Research from music user forums has revealed that the likely culprit is the RICOH FW chip used on the motherboard of the HP dv9000 and other similar laptops. Laptops that have the TI chip do not have any issues. I then purchased an ExpressCard FW card from Sewell that has the TI chip in it and it would not work either. The reason is, (at least I thought it was) that the RICOH chip might also be controlling the ExpressCard controller in the laptop. Is this the BIOS problem you speak of, or might there also be a separate issue with the RICOH chipset drivers?
RJ
The BIOS problem that interferes with these ExpressCard to PCMCIA adapters would not affect expresscards like the one you have. It is possible that the built on firewire on your laptop is conflicting with the firewire card you are rying to use. I would recommend checking the laptop BIOS to see if there is an option to disable the built in FireWire. If not I would at least disable it in the device manager. Then once it's disabled try installing the other firewire card again and see if you have any better luck.
Let me know if you have any better results, or any questions.