I've tried *XDIM MEMBERSET TIME = %TIME_SET%,PRIOR(12) but It doesn't work.
In *select I tried to change
*SELECT (%PY%,"[YEAR]-1",TIME,"[ID]='%TIME_SET%'")
*SELECT (%MESE%,"[PERIOD]","TIME","[ID]='%TIME_SET%'")
with
*SELECT (%PY%,"[YEAR]-1",TIME,"[ID]='2014.SEP'")
*SELECT (%MESE%,"[PERIOD]","TIME","[ID]='2014.SEP'")
and It works correctly.. but I need dynamic time selected from prompt