Create an cell XSL:FO table cell, which can be detected as a signature cell by Adobe Acrobat Sign

Question

I'm trying to create an XSL:FO table structure, which helps Adobe Acrobat/Sign to detect signature cells. I am searching for a single-column, two-row table. The first cell should be the cell where the signature is placed. The second cell is just a label. The label can be in English or any other language. Do you think this is possible? Can I annotate/flag the cell to make it easier for Adobe Acrobat/Sign? Sometimes the cell is detected, sometimes it is not.

┏─────────────────────────────────────────────────────────────────────────┓
┃ <!-- Adobe Acrobat/Sign should detect this cell as a signature cell --> ┃
┣─────────────────────────────────────────────────────────────────────────┥
┃ Signature                                                               ┃
┗─────────────────────────────────────────────────────────────────────────┛

<fo:table>
  <fo:table-body>
    <fo:table-column/>
    <fo:table-row>
      <fo:table-cell>
        <fo:block>
          <!-- Signature to be placed here -->
        </fo:block>
      </fo:table-cell>
      <fo:table-cell>
        <fo:block>
          Signature <!-- This is just a string, could be in any language (English, French, Albanian, ...) -->
        </fo:block>
      </fo:table-cell>
    </fo:table-row>
  </fo:table-body>
</fo:table>