[TYPO3-english] Flexform Problem with default value

[T.M.Snyder]

Hi all,

I havve a T3 V4.2.1 running. No TV.

I have a flexform in my extension like this:
<T3DataStructure>
 <meta>
  <langDisable>1</langDisable>
 </meta>
    <ROOT>
  <el>
   <pi_flexform>
    <TCEforms>
     <label>Labels</label>
     <config>
      <type>input</type>
      <size>2</size>
      <max>2</max>
      <eval>num,trim</eval>
      <default>3</default>
     </config>
    </TCEforms>
   </pi_flexform>
  </el>
 </ROOT>
</T3DataStructure>

Everything works fine, except the default value in the BE is always  empty.
But when the field is empty, the default value of "3" should be inserted.

How could I achieve this ?
Maybe with Typoscript?

Any suggestions or hints?

Thanks.