Many thanks to all of those who answered me !!
Even if I had trouble understanding some of the technical stuff about SmallIntegers (although I should know what immediates are now! :), it should help me get rid of this XML serializer project we've gotta do for 1 week from here!

For the purpose of generating a SmallInteger (from XML ya know..), Object readFrom:'42' works just fine!

As Stéphane Ducasse said, Smalltalk community seems to be truely helpfull and tolerant with newbies like me, and it will encourage me to post questions (less stupid I hope!) in the future!

Thank you again to the Smalltalk community!

Michel.