Apple says otherwise in a tech bulletin.
http://support.apple.com/kb/TA43788?viewlocale=en_US
while saying the SE/30 and IIfx have identical PDS slots, it does however state that the SE/30 PDS connector is different to that in the IIci, or at least it's electrically different to the point the IIci cache card will nuke the IIfx logic board.
So now we have MicroMac who says the Diimo 030 works in the SE/30 and IIci (unless these are diffrent cards!!) and Apple who says that the PDS slots in both systems are not compatible.