[castor-user] build-in function on field

[amlee]

I have an object that I want to map to the column with build-in function:

select a, b, func(c) from object1

<class name="object1">
:
  <field name="a">
    <sql name="a" ...>
  </field>
  <field name="b">
    <sql name="b" ...>
  </field>

 
  <field name="c"
    <sql name="func(c)" ...>
  </field>
  :
  :
</class>

I got the exception like:
"Caused by: org.xml.sax.SAXException: unable to add attribute "c" to
'org.exolab.castor.mapping.xml.Sql' due to the following error:
java.lang.IllegalStateException: "func(c)" is not a valid NMToken.

Is there a way to customize the query when retrieving objects from database?
For example, the column might have something like "case when.....else .... end"
in TRANSACT SQL.

I know I might be able to get the column c and do another direct sql query or
something in getC() to processing the value. But doing direct sql query doesn't
sound right to me.

Thanks!

Alex