geof:
 
Try adding a new column to your table that is type date/time and put your converted values there using a formula.  Here is an example:
 
 
New Table( "Time Example",
Add Rows( 1 ),
New Column( "Column 2",
  Character,
  Nominal,
  Set Values( {"2013-09-01-14:02:33:759000"} )
),
New Column( "Column 3",
  Numeric,
  Continuous,
  Format( "yyyy-mm-ddThh:mm:ss", 19, 0 ),
  Input Format( "yyyy-mm-ddThh:mm:ss", 0 ),
  Formula(
   Parse Date(
    Substr( :Column 2, 1, 10 ) || "T" || Substr( :Column 2, 12, 8 ) ||
    "." || Substr( :Column 2, 21 )
   )
  )
)
)
 
 
Michael Haslam