Concatenate date time and update SQL datetime field

I have a form that captures date and time in 2 separate fields data and time.

I need to combine these fileds and UPDATE a SQL database (datetime field)

The date field is passed like this  DSDATE={ts '2013-11-18 00:00:00'}

The time field is passed like this   TIME_IN1=14:05

How do I concatenate DSDATE AND TIME_IN1 so that I can insert like this 2013-11-18 14:05:00.000 ?