Thanx to everybody!
God only knows why I wrote "72-pin" SIMMs: actually they are (only) 30 !! (I have 10 modules of 1 MB each: four are already installed in my STE, six are available...)
TC_Steve: I appreciate your offer but it is not yet clear to me if I have simply to plug the modules in the socket and then go... OR, according to Stimpy's opinion, I have to modify my STE...