I have the same problem and just posted about it. (I beleive my machine is a sister machine to yours and is almost identical ok it might be a D830, can't remember - but mine is the Dell D630). There is supposely a fix to get the PCMCIA Cardreader working. search "Chun-Nan_PCMCIA kext" Theoretically you could then find a firewire card that works with macosx to get drivers etc. Hope this helps in some small way. - Thanks!
I have a 99.9% working install of SL on a Dell d630 nvidia graphics. (It took a while - but finally had success using a EFI Empire boot cd - retail SL install disk then 10.6.8 combo updater - multifail - EDP combination). My problem is this; My built in Firewire is showing as working in the system profiler. It even works at some level by detecting a video camera/audio interface - but when attempting to actually pass data to use the device it does nothing. Any ideas on what to try? An other idea is to install Chun-Nan_PCMCIA card slot kext - but I don't know that this would do