Well, it appears that very few transfer tools seem to handle it!
TAP2WAV, Load Vader and Oric Explorer fail at dealing with them.
WAV2TAP is OK (since it doesn't work with the help of files data, but only with the tape signal).
I didn't try Oric copy tools but I don't think they would work (Delbock, Multicopy, ...).
DupK7, a Sedoric tool made by André C. claims to be able to load STOREd files (see CEO-Mag issue 183, summer 2005).
So, it seems there's still some work to do on our tools if we want a 100% reliability
