I just queried Technical Support and they confirmed it's not possible from Beatscape.
Dimension Pro and RXP (maybe DropZone also - but I'm not sure) will allow this. If you open a REX file in one of them, there's a button there "Drag-and-drop MIDI Pattern to Track".
Thus you'll have (in a MIDI track) the succession of notes - each triggering a slice.
Advantages: you can further re-order the slices, adjust velocity of an individual slice, and - most important - you can modify the Tempo in real time (on the fly) and there'll be NO artifacts in the audio REX file, because each MIDI note will play a slice, and you just speed up/slow down the MIDI notes - hence he individual slices.
A .wav file can be tranformed in a .rx2 file (REX format) ONLY with the "ReCycle" software from Swedish company Propellerhead.
Hope this helps.
post edited by PopStarWannabe - 2010/04/06 18:07:47