PCI Express Question

[AtmosMan]

I will be buying a new Thinkpad once Intel releases Alviso and Sonoma. I have been slowly building up a list of new hardware I need to get. I compose music and do some digital music editing, so I need a better soundcard than what is provided with the Thinkpads. I want the card to be portable, so I am really interested in a PCMCIA type card (particularly the Echo Indigo Playback Card.) My question is: If in the new T series models, PCMCIA is replaced with PCIe, will I be able to use a PCMCIA card with the new PCIe slot (is PCIe backwards compatible with PCMCIA)?

Thanks for the help.

-Brian