Well, I just got Verbatim ExpressCard SSD 16 Gb - it is recognized as an additional controller and performs uncompromising. Protools 8 says it is a valid volume for all operations.
Anyone interested can see some technical details in this file:
http://svetlinstaikov.com/Files/PerfData.zip
The machine is Dell Inspiron 1520, other hard drives are the internal 5400 rpm 160 Gb Toshiba and the external Firewire 400 OWC Mercury Elite Al Pro 500 Gb 7200 rpm 16 Mb cache.
Hope this information will help someone.
Cheers!