Earlier versions of Cyberflex cards have the same or a very similiar filesystem interface like the Cryptoflex cards. Those cards work well with OpenSC.
Newer versions however are pure JavaCards? and will not work without a JavaApplet?. No such applet is currently supported by OpenSC.
MuscleCard is an open source software containing a JavaApplet? for Cryptoflex cards and has a pkcs#11
library for Unix/Linux and Windows.
FIXME:Did anyone test such a card recently?