per the FAQ, page 3:
"Moves made in the movement phase are considered to be ‘normal’ moves, while moves made in the charge phase are charge moves, and those in the combat phase are pile-in moves. In addition, things that allow a unit to move ‘as if it were the movement phase’, allow a unit to make a normal move."
Furthermore the FAQ goes on to show a chart dictating what moves are classified as:
Type of Move = Normal, Move Distance = Move Characteristic, Restrictions = Cannot finish the move within 3" of an enemy model. Units can run or retreat when they make a normal move.
So we see that a normal move is classified by a set of restrictions, none of which exclude running. In fact it states that running and/or retreating are indeed included as 'normal' moves.
So yes, you may use the ability to retreat from combat and it was count as a normal move which is a retreat.