Apache FOP: zindex does not appear to be working in overlapping blocks

I am a FOP newb. I am trying to show text on top of an image by using block-container's and zindexes. The image is always on top though. If i remove the image, i can see the text, so the text is under the image.

This is inside of a table cell. here is the relevant code:

<fo:table-cell padding="0.000pt" text-align="left" display-align="before">
                <fo:block>
                  <fo:block-container z-index="2" position="absolute" left="0.913in" top="0.139in" width="0.946in" height="0.198in"开发者_运维知识库 overflow="hidden">
                    <fo:block><fo:inline font-family="Verdana" font-size="8pt">Leasure Station</fo:inline></fo:block>
                  </fo:block-container>

                  <fo:block-container z-index="2" position="absolute" left="0.091in" top="0.431in" width="0.302in" height="0.239in" overflow="hidden">
                    <fo:block><fo:inline font-family="Verdana" font-size="8pt">#1</fo:inline></fo:block>
                  </fo:block-container>

                  <fo:block-container z-index="2" position="absolute" left="0.653in" top="0.431in" width="1.186in" height="0.177in" overflow="hidden">
                    <fo:block><fo:inline font-family="Verdana" font-size="8pt">ASDF1234QWER</fo:inline></fo:block>
                  </fo:block-container>

                  <fo:block-container z-index="1" position="absolute" left="0in" top="0in" width="48.5mm" height="20mm" overflow="hidden">
                    <fo:block><fo:external-graphic src="url(.\fop-1.0\img\orange_s_text.png)" content-width="48.500mm" scaling="non-uniform" content-height="20.000mm"/></fo:block>
                  </fo:block-container>
                </fo:block>
              </fo:table-cell>

moved the block with index 1 before all the zindex=2 blocks and it worked. whatever.