Firewire eSATA card

Has anybody sucessfully used a firewire conversion card into an Express laptop slot?  This card plugs into the Express Card slot (also call eSata) and provides two firewire 800 ports.
 
I've read reviews of folks that that have had trouble making these work.  It sounds like you can't get power over the eSATA port
but has anybody used this and made it work as firewire port?
 
Thanks.