[TYPO3-english] Select box in flexform

[Sergio]

Hi,

I'm building a flexform for my extension and I have a setting what I want
to be displayed like this:

http://typo3.org/typo3temp/pics/100002010000021D000000A21269C585_62383a2581.png

I mean, a select with two columns: left for selected items from a table,
and right for available items.

The code for this flexform is:

<settings.publisher>
  <TCEforms>
    <label>Label</label>
    <config>
      <type>select</type>
      <foreign_table>tx_extension_table</foreign_table>
      <foreign_table_where>ORDER BY
tx_extension_table.nameASC</foreign_table_where>
      <size>10</size>
      <minItems>0</minItems>
      <maxItems>100</maxItems>
    </config>
  </TCEforms>
</settings.publisher>

But it's only viewed with one column for selected items. Isn't that
possible with flexforms? Am I missing some parameter? I see you can do it
with TCA.

Any suggestions?

Sergio