IBatisNet Insert返回主键ID

MS SqlServer:

<insert id="Insert" parameterClass="Person"> 
   insert into PERSON 
    (PER_FIRST_NAME, PER_LAST_NAME, 
    PER_BIRTH_DATE, PER_WEIGHT_KG, PER_HEIGHT_M) 
   values 
    ( #FirstName#, #LastName#, 
    #BirthDate#, #WeightInKilograms#, #HeightInMeters#) 
   <selectKey property="Id" type="post" resultClass="int">  
   select CAST(@@IDENTITY as int) as value 
   </selectKey>  
  </insert>

MySql:

<insert id="Insert" parameterClass="Person"> 
   insert into PERSON 
     (PER_FIRST_NAME, PER_LAST_NAME, 
     PER_BIRTH_DATE, PER_WEIGHT_KG, PER_HEIGHT_M) 
     values 
      ( #FirstName#, #LastName#, 
     #BirthDate#, #WeightInKilograms#, #HeightInMeters#) 
     <selectKey property="Id" type="post" resultClass="int">  
     select @@IDENTITY as value 
    </selectKey>  
</insert>