I have a Toshiba 300CDT and both Sportster Winmodem PC card and a external IDE disk drive card.
I have tried 6 among the major installations, but the only two which recognized the existence of PC cards during istallation (and so they asked if I need support for PCMCIA) were SuSE and TurboLinux. RedHat did not asked.
Both SuSE and TurboLinux, after loading the extra-disk, recognised the external drive and so I can partition and format the external disk, but did not recognised the modem card.
Since I have not succeded to arrive at the end of the first boot (see question nb.4 on this forum) I cannot say if it will be possible to recognise the modem after launching Linux.
Perhaps it can be of help to you to try with the abovesaid installations.